PCP let me know if you decide not to rebuild the 307.

I'd love to have one of the old pull type 7' Servis (owns Rhino) cutter. They had the little mushroom looking shear bolt. Good, stout old cutters.

There's a place in N AL somewhere called CR Manufacturing that makes forestry packages for JD (and other, lesser brand) tractors. They should make a STOUT belly pan that would protect your tractor very well doing what you're doing. They make full protection packages for those tractors that get used mowing highway right of ways and the ones that have boom mowers mounted on them.

They sell most all that stuff both in packages and a piece at a time. Beware, it is NOT cheap, but will usually pay for itself several times in damage prevented.