Finished cutting out the braces and test fit the replacement pats.
Ground most of the paint off the inside.
Biggest project was refitting the floor patch. I noticed that the patch wasn't sitting flush on the floor so I cut off the seat riser flange and did some hammering and pushing and reinstalled the patch. Much better now. Floor is level and flat and quite sturdy. There will be a bead of body caulking where the seat riser meets the floor.