Steering wheel options for us Early A drivers

Thanks for the help. Wow so many choices on the Grant Site. If I can find one of those used it would be great. I still need some clarification: do I need a special adapter kit? my wheel has 2 bolts, all these new ones have 3 bolts? some have 5? Do these new wheels have the same type of turn cancel peg sticking out of the bottom?
Lastly, I read the install instructions for the horn switch, it is saying something about sticking some disc onto the switch? but then if I need to remove the wheel, how do I remove the adhered-to disc thingy??? little confused.

And finally size, my wheel is 16.5 inches in diameter. Would 15 be a good change?
With power steering you can use any diameter you choose. Manual steering needs a bigger wheel for more mechanical advantage.