Need advice... what is my next step??

Hey guys, thanks for being patient with me. I am in a bit of a dilemma right now.

My dad and I are about to start building our 1969 Camaro. Right now i am in the parts collecting phase. I would like to get started on the body and chassis work soon.

So far i have:

DSE Mini Tubs - Not installed
DSE SFC's - Not installed
DSE Quadra Link - Not installed

My seeking advice pertains to the purchase of the rear end, rear brakes, front clip and wheels.

I am planning on running a Currie 9" Rear end, Baer brakes.

What size wheel/tire combination am i best off running? I originally was thinking 18x12 w/ 6" backspacing & 335/35/18 for the rear and 18x9 with ?? backspacing & 275/35/18 for the front, however, after SEMA i have quickly realized that not many manufacturers are into custom making reversed lip 18" rims in those widths & backspacing. There are a ton of choices available in 19" or higher. Is there any pro's or cons to running 19" wheels in my application? Will they fit properly?

Another part to my wheel dilemma is, how do i know what hub length to make the wheel if i do not have my brakes and rear end? I want to make sure the wheels will clear the brake caliper.

The second part to my dilemma is, what dimensions should the rear end be made to? I have been told to buy the wheels, mock them up in the wheel wells, and measure the hub to hub distance. That part sound good to me, however, i need to solve the wheel dilemma first so this is kind of a viscous circle.

Basically i need to know what my next step should be and how to go about making the right choice in that step weather it is to buy the wheels first, or to buy the rear end & brakes first.

Trev