toledojff, here's a link to my not so detailed build thread.
https://www.tractorbynet.com/forums/build-yourself/269134-tractor-skid-pan-toolbox-passenger.html
There's basically 3 "crossmembers" that take advantage of the limited attachment points on the tractor. That created some spans that I felt were too long to support the machine (on a stump or rock) with the 1/4" actual skid plate. (there are 3 pieces to the plate as well) I felt that anything thicker (heavier) would be a real chore to remove for service or cleaning out the piles of chaff, leaves & sticks that accumulate bush hogging the jungle of stuff that I'm mowing, that stuff is a fire hazard. I set out to make a bullet proof tractor similar to what I've seen them do to tractors that are modified for "right of way" mowing on utility easments, you may be using your tractor in a more traditional agricultural situation and not need to go to some of the protection levels that I have but the basic attachment points will prolly be used by your welder guy.
I'll add a few pics that explain some of the "tabs" that you can see in that post that might explain a few things.
this is the rear "pan" and there are 2 "rib's" welded to help with the long span between mounting points. The one is bent around the factory fuel tank bracket on the tractor. They are just 1/2 x 2 bar. There is also one of these bars bolted between 2 x-members. (2nd pic. left side, bottom)
This is the center section, again there are 3 of these bars that bolt (vertically) to the 2nd & 3rd x-member. They only are there for the pan to push against if needed and are not attached to the pan.
All the "flat" tabs are simply to bolt on the pans. There are nuts welded to them.
The front area under the engine was about 3" higher than the rest of it, I wanted to maintain as much ground clearance as possible. This again uses the 1/2x2" flat bar stood vertically. It's supported in 3 places and being so close to (and a few inches higher than) the front axle, has never seen a rock or stump. This front section, at least in my use seem's only to be a "belly pan" only for stick - brush protection and not so much a skid plate.
see the 3" jump up for the front Those painted 4" channel's were for possible support for side engine guarding that I
have not needed but were handy for this.