Flying the plane is 1 thing... shooting the guns another.
I'd suggest 109G14, 109K4, Ta152H1 for 30mm practice. The Ta152 isn't as easy to fly but has 50% more ammo. Or practice with the 110G if you need a lot of ammo, but you probably won't survive too long in LWA environs.
In short, get used to the ballistics on more normal craft, then use that lead/computing/mental stuff you gain from them on the 262.