Thanks for the response- I knew I had to go with one of those 3 options, just didn't know which would be the biggest pain or most costly- modify the stock and not be able to change my mind on the DBM down the road, or go the high $$ route and get a DBM from one of the aftermarket guys. THen there's the issue of reselling the factory DBM I already have (and have never used, but spent just shy of $100 for).
Fortunately, my smith was in need of such a DBM so we swapped- I ended up with the BDL floorplate option that he had on hand, which requires no extra work to the stock or action or anything, and he ended up with my factory DBM for another customer plus a few extra of my $$ make up for the price difference in the parts. Everyone's happy, and my build is now safe and remains versatile should I like to change my mind on the bottom metal down the road.