reducing build size

I might be ahead of myself here since I have not finished my initial 30x30 build however:

Lets say that I want to cut out a small aluminum piece like an A arm for an RC car and want extra rigidity. Can I quickly reduce the size by poking the pipes outside of the clamps a bit? Right now I have 30" rails, so could I just slide everything in a bit and re-calibrate to effectively make it smaller?

Sure, but I think you will be better of concentrating on just getting the metal as high up and close to the gantry as possible, every mm counts. I cut my motor mounts on a 30 x30 no problem. You can also add mid span supports if you really want to get crazy with it.

Awesome thanks!