W4's Maximums

[peteinsf]

All,

I have to put a Astro mobile in an airplane and the pilot(s) dislike the "mode" up/dn button on the W5/W7 heads.

Aircraft radios all seem to have the "dial" way of QSYing and they would like it if I could swap W7 -> W4.

My questions are:

a) Can I put a W4 head on a W7 radio and have it work (I would assume not, hacked maybe)?

b) Can a W4 radio have 255 modes, zones and user program scan.

Thanks, Pete