Hey, I have a 4 door 97' XJ, My rockers are rotting off and I plan on replacing them with some steel tubes rather then get more factory ones, Where would I get the measurements, and where would I weld them to?

Thanks!

Most people use 2x6x3/16 wall or 1/4" wall.
Measure how long you want them to be and weld them at every possible point of contact and supports to the frame are a good addition

Do a search in the Fabrication section there are a few write up there that might give you a few ideas on how to do it.