Actually Klam you are mistaken,if you set convergence to 300 and shoot at a target at 200 the rounds will be low,not high! the rounds come up to piper at convergence and never rise above the line of sight.
...Are you talking about in the specific instance he's describing, or in general? If you're talking about in general, rounds can go well above the pipper with certain convergence settings and certain guns. The easiest one to see it with is the 30mm on the K4. Set it to 500 convergence. It will shoot low out to around 100-150 yards, then will rise above LOS, in the 350 range, then drop back down to the pipper at 500. To combat this, I think my convergence is set around 225-250 on the 30mm. This makes its arc close enough to on the pipper for me out to about 400, with noticable drop at 500. Not that I shoot at that range unless it's a nonmaneuvering guy trying to run.
Another thing about convergence and shooting "in range"...
When the enemy icon switches from D800 to D600, he's at D700. When it moves from D600 to D400, he's at D500. Etc., etc. So if you have your convergence at 300, wait until the icon changes from D400 to D200 and he'll be at 300 yards.
Just wanted to reinforce this as I was going to mention it as a fairly major difference between here and WBs. In WBs, when it went from 500 to 400, it meant he'd crossed to within 400 yards. In here, when it goes from 600 to 400, it means he's crossed the 500 yard line. It's a bit of a different way of looking at it here. When I first came over, I expended a lot of ammo at guys whose icons said 600 or 800, not realizing I was shooting 700-900 out.
As to convergence, on .50 and 20mm equipped planes, I stick with 450 yards as my convergence. I do most of my shooting inside of that distance, but I like the versatility it gives me. If someone's not maneuvering at 600 yards I can still put a decent volume of fire on him without trajectory coming into play too much, and if they're pulling away at 400, if I hit them I hit at convergence. My bullets are a bit diffuse inside that range, but I find it to be good enough.
The one thing I suggest is, try a setting and stick with it for a while (couple weeks at least) so you can give your brain time to get used to the sight picture in different circumstances at that convergence. IMO one of the worst things you can do for your gunnery is to constantly be fiddling with your convergence.
For guys that aren't maneuvering much trying to run, I use the zoom feature to get right in on top of them. As soon as they start to wiggle though I return to default FOV. I find zoom messes with my ability to lead them effectively in a hard maneuver.
Wiley.
