1" vs. 1-1/4" rotors

[kevinr1970]

Alright, I have seen this brought up in conversation before when talking about buying drop spindles.

I am real close to getting my crew swb project jump-started but have some questions in regards to this.
My crew and swb donor are both 1987 model year.
The swb donor is an ex-USFS Custom Deluxe, v6, manual stripped down model; I assume that this truck has the 1" lighter duty rotors. (are they really a "lighter duty" rotor?)
The crew is going to be swapped over to 1/2 ton suspension and will be completely rebuilt including brakes at this time.

If the donor has 1" rotors, can I buy new spindles for the 1-1/4" rotors, new 1-1/4" rotors and the the accompanying(sp?) parts?
Are the 1-1/4" rotors that different in braking performance to even bother considering this?
If I end up switching over the 1-1/4" rotors, what other parts am I looking at having to buy to accomodate this?

I already have 3" drop springs and am thinking that I might end up with drop spindles too later, after I see how much clearance I have trying to get up my driveway. For now, I would like to avoid having to buy spindles if I don't have to.

Thanks in advance!