The Zeke isn't much of a diver - too light. So, I dive. The 5 zeke can actually dive to higher speeds than most realize. Come in fast from above and you'll really confuse your opponent. He'll be used to Zekes low and slow and turning. If you dive on him, he probably won't have the speed to out-run you. He'll probably panic and start to turn hard. That's when you chop your throttle and become a turny zeke again. You'll win. If he dives away from you, then he knows what he's doing. In that event, you're probably best breaking off and re-gaining your perch.
One thing I've learned not to do in a zeke is press on alone towards an enemy base. I've found the zeke to be at its best high over a friendly base that is under attack. That's when you'll be able to "boom and turn" with support from your mates.
When choosing your variety of zeke remember that the -2 is the most maneuverable, the -3 can roll like a 190, and the -5 replaces one of the .30 caliber guns in the nose with a .50 caliber. That makes a great deal of difference in a close turning fight when the only guns you can get on target are in the nose. The -5 dives better and is a bit faster than the other two but is slightly less maneuverable.