Schatzi, I highly recommend 250-275 convergence on the Spit I. Thats where I have the best luck anyway.
As for flying it, you almost have to treat it like an underpowered P38. Rudders. Lots of rudders. Pull on the stick more than you would the other Spits or the Hurri, you can easily roll inverted and remain that way in loops or yo yos without worrying about the negative G cutouts if you keep pressure on the stick and rudders. I've had the plane almost at a dead stop rolling out of an Immelman and not lost engine until the very last bit of the rollout. If you time things right, you can do it without any cutout at all. I find it often works better to barrel roll to line up on a con than to try using the stick when they are evasive, using the extra space the roll gives you to help line up on target, rather than trying to make small, quick corrections with the stick.