3aj,3tb,4pt

[point75]

hello everyone

thanks to all for the knowledge accumulated here. i am trying to build an overlander from a 3aj, 3tb and a 4pt that i have collected over the last year. i am basing the bike around the 3aj. originally i was going to use the motor and wiring from the 4pt but it seems the gearbox in that is the worst of the lot.....
the best gearbox is the 3tb. so my question is: are the ignitions the same on a 3tb as a 3aj, hence influencing which bikes wiring i choose to use.....
my second question is: which set of carbs(or combination thereof) should i use with an arrow exhaust and 3aj airbox. there seems to be small differences between each pair which add to my confusion.....
my third question is: what is the best gearing compromise for off road and highway. i would like to be able to cruise at 70 and still be able to hoist the front in 1st and 2nd off the throttle.

thanks in advance and apologies if these questions have already been answered.

cheers

point75
ps trying to do all this as cheap as possible
pps will want to sell left over bits once bike is finished. email if you need anything