Michael, very exciting. I envy the opportunity yer being afforded.
I got to see first hand some of Clay Harmons 12x20 negatives and the resulting prints.
made me start to contemplate it.... they are just gorgeous and such a wonderful format.

I dont shoot 12x20, but do shoot 7x17. I use Efke PL100 (think its labeled as Adox now at JandC) and it gives great results. I dont do much of anything aside from pt/pd printing with the negatives (now at least, started with VDBs), but love the film.
I sort of jumped into the pyro dev thing with both feet. Its really not that rough of a learning curve. Efke 100 and the JandC 400 films are both great. havent shot any Tmax, trix, or Ilford films in ULF but imagine theyd be just as good as the 4x5s.