aluminum flywheel and overdrive gear set

i'm working on a '69 pontiac with an M20 4-speed/3.55/25.9" tire.  I will be building an M22 to install in the car.  Is the swap to a 26-spline as easy as bolting a 26 spline 11" clutch onto the flywheel?  Do i need a different pilot bearing?  

While i'm there, does anyone have any words on aluminum flywheels -- i.e. streetability, any disadvantages to having less inertia at the flywheel?

I'm thinking about building a spare 4-spd with the overdrive gear set.  Does anyone have any experience with one of these gearsets?  Is it noisy running in overdrive through the cluster?

While I'm here -- regarding billet wheels, does anyone have any links to pictures of a 69 gto with 17" wheels?  I'm concerned this will be too much wheel for my car, but cannot find pictures of the vintiques 17" rally II.

Thanks for anyone's time and consideration