Sorry can't help. My bass guitarist and I once had ago at making thiele cabs. Got the plans from Electro Voice, which were freely available over the internet. An 8’x 4’ 3/4" birch ply sheet was enough for three cabs. Got the timber merchant to do the all the cuts apart from the speaker baffles, so for us it was an assembly job. The one I made, I stained to match my Imbuya combo, it was then oiled and hand waxed. I even found where I could get hold of some wicker cane which I aged, again to match the combo cabinet. Even the ‘Boogie’ logo was copied and put on the new cab. Then came the day to test it out, I loaded it with an EV and went to put the combo on top – at that point I realised Mesa had changed the dimensions of their thiele cabs to suit their combos– doh!!! We hadn’t checked beforehand.
Ian