I have 4 Isophon ph-2132 coaxial drivers 97db. They have Alnico magnets, a high Qts and should be fine in an open baffle. The issue with re-coning Isophons is that there no OEM spec parts that I know of.
I also have a pair of Wild Burro Audio 8 inch Alnico drivers for open baffles. I'm going to get these going first. I have some 1.5 inch thick pine panels to mount them in and will also try them in a flat pack enclosure from Parts Express, with the backs off or vented.
https://www.parts-express.com/PA-Kno...2-Driv-245-324