Thanks guys.
Jon, no plans just kind of winged it, but I had a basic Idea in my head. Since you asked I'll go ahead post some info here to duplicate it, it's very basic.
Here's the materials with what I paid for the small quantity just for general reference:
Carbon Steel Angle 2"x2"x1/8" 6' Long $19
Carbon Steel Rectangle Bar 1018 1/8"x3/4" 6' Long $14
4' x 4' Expanded metal sheet, Raised, Carbon Steel, 3/4-#9 Strand size .144" $89
Couple of 1/4-20 nuts, bolts and washers.
1 Can Rustoleum High Temp Flat Black (barbecue/stove type paint. It's an amazingly good match for the flat black plastic grill of the tractor, and it's going to get beat up anyway.)
The guards external dimensions are 20 3/4" wide, 28 5/8" high.
The expanded metal needs to be cut at least 1/4" per side smaller than this so there's plenty of room to get the ends tacked onto the back of the metal cleanly without it showing on the sides or front.
So the expanded piece will be cut approx 20 1/4" x 28" or whatever works for you.
This expanded metal is big and easy to tack weld the dozens of ends on the back, I've only welded a few things ever and managed this project fine with .030 flux core wire.
The top back just has a couple more pieces of the 2x2 bar welded in appropriately to hold on to the round bar on the tractor. The guard just drops on the top and is bolted at the bottom...
The 1/8"x3/4" bars down the sides that the mesh is welded to allows the whole thing to flex easily enough to generally follow the contour of the factory guard and just get bolted at the bottom.
I used a remaining piece from the 6' bar of 2x2 for the attach point on the existing bottom bolt holes on the tractor, then used a piece of the 1/8"x3/4" and welded on a close-ish angle on the front and then drilled through the front and the edge together so the bolt holes line up. Don't look at that weld too hard. That one I'm not proud of but it's not going anywhere.
Just push the bottom so it flexes up against the angle piece and drill it through. No measuring for that part, just match drill through the whole thing and make sure you hit the back angled piece somewhere near the middle.
If you notice I did notch the bottom 2x2 on each side so it could fit a little deeper over the tractor's guard... this helps it fit almost perfect up against the angled mount.
One on the fly change I made was these 3 3/4" strips on the top on each side behind the mesh. The mesh is very rough stuff and this helps it go on and off without as much destruction to the tractor guards paint (not that I really care it's never coming off) it also makes the amount of bend necessary less and a little more natural and easy to do.
Most of the two 6' steel bars are used up, and you'll only use about a quarter of the expanded metal sheet, but you can't buy small pieces of expanded metal cheap at least not around me. I shopped a lot. It was the same price for a small bit that may have been too small or the entire 4'x4' sheet shipped leaving enough for future projects like closing up the back of my grapple a little so stuff doesn't stick through it and kill my hydraulic lines again.
That's it! Hope this helps someone.