It seems you've little option but to practice informally; it's not the kind if thing you can do via correspondence.
Now, are you planning to handcraft a matched pair of ya, haya and otoya, to go along with your yumi?
I believe I shall attempt to manufacture arrows, though I will have to find a source of flights, and do not know whether left hand AND right hand paired sets will be practical.
I will almost certainly purchase modern arrows for prctice until I have proven to my satisfaction that arrows I make can do the job.
I will definitely need a 3finger glove for my right hand, and possibly a guard for my left forearm.