Todd,
The pads are a bit bigger have not measured and figured surface area but would guess a third bigger. Have been told the piston area is what makes a difference in clamping so if all things are equal such as caliper distortion and ability to resist boiling then the same size piston area no matter the number of pistons will give you the same braking. I want to think the more modern design of the Outlaw caliper would result in better brakes but…. will just have to wait and see.
Since you are interested in brake upgrades here is a view of the rear brakes I am working on.
This is on a Tiger rear end but would work on an Alpine rear also. The rotor is off an alfa has been reduced in diameter and also had the center hole opened up to fit the hub. The caliper is from a Merkur Scorpion, made up my own weld on bracket. The piston surface area of this caliper is right at half the front caliper so should be balanced from what I have read and learned about this brake stuff.
The Merkur caliper has a built in E brake that is cable operated the plan is to use a set of Ebrake cables [Lokar copies] and hook it up to the stock e brake handle.