Hawg, sorryto hear of your troubles -- fortunately that's only a flesh wound.

I've done several of these conversions.

I mount the ply LG block in the belly on the forward side of the bulkhead that the wings butt against -- this location puts the LG just slightly ahead of the LE of the wings & gives me a solid location for the LG block. I always cut the belly open & glue the ply LG block to the bottom of the ply perimeter frame, with pine triangle stock fitted to the inner sides of the ply frame. The front of the LG block is fitted with a 1/4" balsa semi-lunar bulkhead that is glued to the belly skin & belly stringers. Not a single failure yet.

Note: I also bend the LG slightly to give a little bit of toe-in.