so jatzy, your description was pretty dang accurate, i found out why i had thought they were angle iron and 3/16" thick which did seem kinda too much. But nope they are pretty much all really big 9 1/2" C-channel pieces like you had said. Someone had put that 3/16" angle iron against the c-channel piece on both sides of wheel well on the long ones not the inside short panels. But thank you for the information and luckily haven't bought anything for that yet. I couldn't ask for more when it comes to this site, it's great (even if I'm proved wrong.)
So as you can see here there i s the 3/16" angle iron behind that flap of the c-channel. the other part of the angle iron is underneath that, so it just seems as if they put that there to reinforce the heaviest rust area. Not the best picture, thought it would do until i got home and looked at it, but as you can see the angle iron is still pretty much largely intact it was just the piece it was attached to that was rusted out.
So here is the huge 9 1/2" c-channel pieces you mentioned, i should've examined it more and noticed there was no seam and it was all just one piece but oh well, hasnt hurt anything yet. they are still in very good shape with little rust even being that close to the wheel well.
A shot from behind the wheel well, main frame still looks great, just dirty. So figured out they were all riveted together, which was a bitch to removed but at least i know they are all pretty much still solid. So i'm thinking the square tube might be the way to go here now. seems easier too.
Here are the rubber pucks you mentioned, and since the other two by the wheel well are square and twice that size they had to have been replaced at sometime or another, you'd think so anyways.