Well, I've sent out my LED drive board and ordered the parts. The board proved to be large with the optocouplers, at seven inches long it cost $50 frim OSHPARK. Perhaps I should have stayed with the discreet transistor version for the FET gate drive?  Hopefully the isolation aspect will give it a small bit of reusability. I may make a sized down version of the board for future use, some I don't think my design requires isolation from the 12 supply. But, for the moment reworking the board for lower cost would have just delayed getting a prototype built. So we will stick with that. I've updated Github with these latest changes.