Bracing cab prior to floor repair

[Grandpas 72]

Hello all,
I have a question about adding additional bracing prior to cutting out old floors, cab mounts, and floor supports. Are there specific locations that square tubing should be attached in order to keep the cab square when replacing panels? Is there anything wrong with using existing bolt holes and bolting the bracing in instead of welding it? I have searched the Internet to see how others have done it but it doesn't seem like any two people have done it the same. Is there a blue print out that shows the best locations to attach bracing? Any help would be greatly appreciated.
Thanks