I think i broke rear main bearing

On the gasket thing I've done them both ways. As thin as the gasket that sometimes comes with a new pump is, I can't see it helping much vs a perfectly machined flat surface as are both the pump and the cap it bolts to.
In the case of the problem posted in the thread any heat applied (welding, brazing etc) would make me wanting to take that cap to a machine shop and have a few thou shaved off the pump mount surface to guarantee flatness