scrounging up materials to build my rear bumper and had a few questions.

I have some 2x4 square tube one is marked 1/4" thick and the other is marked I think 11 guage.
I know a lot of folks use 3/16 and was wondering where 11 guage fits in as far as 16's of an inch, and would it work or would I be better to use the 1/4.
3/16 might be preffered I kow but I already own these peices.

also I saw on the bumper build thread guys are using C channel for sldining in the frame.
is that preffered over the square tubing?
I think 2x4 square slides in the frame, correct me if I am wrong.
maybe use the 1/4 for the frame mounts and 11 guage for the bumper???

and for shackle hangers Rockstomper sells 1X4.5X3 at 20 a peice.
I can get some 1X3 at $10 a foot and figure I could cut and drill my own for much less $$ just more time

Is this crazy tough to drill and cut ( I have a drill press and chop saw)
and is there any reason to use the 4.5" wide vs the 3"?
Is 3" enough material welded on to be yanking on to get unstuck?

think thats all for now
TIA
Brian