I do have a question. You mentioned barrel rolls and scissors with low/cut throttle to push an overshoot on a Con coming in fast but what if they are matching speed and coming from low? Are there some other effective counters when I have someone on my 6 and I cant shake them?
The first part of defeating the bad guy on your six is to see him early enough. Live in a world of paranoia. Check your surroundings (not just your six)
constantly. When I'm in a fight, I'd say less than 75% of my mind is on the guy I'm fighting, the rest is on what's going on around me. You don't need to take your "eye" off your target necessarily, you can just pay attention to the periphery as you roll through the fight, with just some well-timed glances into blind sections of your environment.
Anyway, what that means is that if you're doing your SA job well, the guy crawling up behind you is no surprise. He may still be there, but you know about it in time to think.
Getting an overshoot is more about closure rate than actual speed differences between you and your opponent. Even if you're both about the same speed, if you can turn so he approaches from your side, he'll still have a high closure rate. So, that's my first/favorite option. I'll turn to the side (usually to the right, and usually about 100 degrees), generally slightly nose down (10 degrees?) to retain my speed, and with the goal of having him approach from my side-rear. I'll start doing this turn when he's about 1.5 out, level back out, and as he comes through D600, I just pull up into about a 30 degree climb (he'll often shoot at you right there, and your flightpath change will disrupt his aim). I hold this climb for maybe 1/2 to 1 second, watching my opponent to judge his speed. 99% of the time he'll be set up to zoom past me (overshoot) below and behind me. If this is the case, I just roll over onto his six and go from there. In this case, I'll have initiated this maneuver with a nose-low
right-hand turn, leveled out, pull up, and rolled
left onto his six.
I prefer to initiate an overshoot while I have nearly equal speed with my opponent. I'm going to lose some speed with my turning, and once I get onto his six I want to have enough speed to do something about it. Of course, I don't always get what I want...
An opponent crawling up on my six at nearly equal speed gets tossed into one of two groups for me right off the bat.
Group one, is the guy who's coming as fast as he can (even if he's barely closing on me), and just doesn't have any choice but to barely catch me. He's generally easy to get to overshoot. He's more concerned with you getting away than anything else, and isn't considering you much of a threat. He'll fall nicely into the maneuver described above.
Group two, is the guy who's regulating his closure rate to give him the shot he's looking for, and intently watching you for signs of your intentions. This guy is dangerous, and probably won't fall for that previously mentioned tactic. Overshoots don't work nicely with someone who's regulating closure. And unfortunately, it's tough to describe how to beat this guy, because as soon as you shift tactics, he'll probably adjust and shift his as well. In general terms, I'd be looking to reverse back (low yo-yo) at him for a merge. Second choice would be something along the lines of a rolling scissors, next choice might be a quick flat scissors, or a descending spiral if I'm high enough. Generally, I'm thinking in that order, because those tactics get more energy-expensive, and I'll run out of options sooner. Regardless, I will
not pull my nose up unless I
know he can't quite get to me. You're going to start out reacting to him (which is bad). You'll either die, or end up reversing the roles and causing him to react to you. He's going to start out dictating the terms of the fight. One "trick" that seems to work well for me is to convince this guy that I'm predictable, in order to make his attack predictable. To do that I''l start out with that right turn so get him closing form my side-rear, and level out, just as mentioned above. But as he closes to guns-range, I don't pull up and roll onto his back. I push
down instead. That almost always seems to get him briefly out of sync, and allows me to keep my speed up as well. It'll be a brief dive of maybe 10 degrees for about a second before I level out, and adjust my heading. I may be able to then turn for a more normal merge, or my "normal" overshoot/barrel roll defense may work "properly" on his next pass, because while he recognizes the set-up, he doesn't really know my intentions (and even I may not know, until the last instant as I judge his approach...)
Now, if the guy crawling up on you
is a surprise (SA failure), you've already screwed up, and will probably need to pay for it with a more expensive manuever if you don't have time to judge/set-up anything better. A quick break turn, or jink, or one, two, or three scissors may get him out of sync with you, and give you some breathing/thinking room. You'll be considerably slower/lower E as a result, so going from there may be difficult, but not impossible. A split S may be a good option. Pulling nose up would probably not be a good option!
Another consideration for the guy barely crawling up behind/below you is whether he can
maintain that closure long enough to be dangerous. Sure, he's catching you, but will he get close enough for a shot? A slower plane with some retained dive-energy maybe? Maybe all you need to do is level out, while he continues his slight climb (and slows as a result). Let closure cease, and extend away or maybe even take it up into a rope.
Last resort, go nose-down and dive away. Or maybe go nose-down to pick up speed and
appear to be diving away (convince him to WEP it to keep up!) and then set him up for an overshoot...
I would avoid getting too slow too quick. Don't be afraid of it, but realize that getting slow does limit your options to some extent. It also gives you some different/added options, but overall it's generally a disadvantage, particularly against someone experienced.
The key is to not panic, and think about the hows and whys of what's happening. SA gives you that option. A plane like the pony does have some very strong points, but you need to have your head wrapped around the situation to capitolize on them.