First, in regards to landing gear make sure that if you kick them out it's not for very long (I rarely do it for more than a second at a time). In a committed turning battle they're not going to help much. Use them in dives to prevent overspeed, and as a last-ditch attempt to force an overshoot, but otherwise.
When I have altitude and range to work with, with an enemy diving on my 6 (anything other than from directly above) I let him close to between 1 and 1.5k out, then roll hard either a Split S or a low Yo-Yo and try to pass back underneath him. In theory, he'll have too much E to follow and will have to pull out of his dive to reposition. During the interim, you can either go nose-down and use the Hog's dive speed to withdraw, or try to neutralize his altitude advantage (this works best if he has a high rate of closure so he can't reverse on you as quickly).
Often I'll follow up my first Split S/low Yo with another one to reverse again. If the bad guy was dropping on me with enough airspeed he may have overshot his dive and blown a significant amount of E trying to pull out. He's likely now below me and handed me the E advantage, so I can drop in behind him. Depending on what and who you're matched up with, you can generally turn the tables within 2-3 passes, if not on the first one outright. Watch out doing this against Typhoons and Tempests, though. Something is seriously punked with their flight model, as I've seen them pull off some ludicrous cornering at speeds well over 400-500mph and manage to pull enough lead for the shot. Otherwise, it works against virtually anything that has a slight or significant altitude advantage/airspeed advantage.
If your opponent is at roughly equivalent altitude and speed, enter a nose-low turn in one direction and keep vis on your target. It doesn't need to be a high AoA turn. This will allow you to build up speed, and pull your opponent in closer (the biggest problem with trying to reverse on a guy at long range closing on your six, is that if you get around on him, 99% of the time you'll end up eating lead from a HO). Once he's closed in (again, usually about 1k should do the trick) execute a hard nose-low break (again, doesn't need to be a Split S, a low Yo will work, as well). continue pulling through the bottom of your maneuver and go vertical. Square up your opponent in the center of either your up or forward-up view and keep him there as you come over the top. Roll as you pull through to keep your target centered. Executed properly, your opponent will lose you below his forward view when you make your break, and if he maintains his turn as you come over the top (You should be in something not unlike a barrel roll) it should drop you into position for a shot.
