[asid61]

6 cims is not for pushing, because the 120a breaker basically limits your torque, even if it delays a few seconds. Your wheels will lift before that happens at lower speeds (~7fps IIRC). It does, however, give you much better acceleration.
The main problem with a 6 cim swerve is that you lose all your cims that could go to a manipulator. Plus, you either have to do a central gearbox or go with a 6-module swerve.
Using centralized gearboxes saves weight (chain weighs very little as a matter of fact) but at the cost of not being able to do complex maneuvers. For programming purposes, a simple crab would work better in my opinion, but mechanically it will be hell to line them up due to chain spacing.

The chain for crabs also has to be designed around for anything that goes above the chassis. The high number of chains also can lead to faster breaks, so using #35 chain could be an advantage maintanence wise.
Chain weight is 0.087lbs for #25, 1.8lbs for #35 per foot.

One way to line up swerve modules is to stretch a piece of surgical tubing between the end of one wheel's axle to the end of another and tie it off there. That keeps both wheel facing forwards. Then you calibrate at 0, and remove the tubing.