I can't find an 8 lb jug of H4350 and when I find R16 it is (after tax, shipping and hazmat) about $75 per lb (limit of 2 lbs) so I have not bought it.
I am on the notification list at several places for the H4350 but no luck yet. I have to drive at least an hour to get to anyplace that sales powder so I don't just drop by a shop and see what they have on hand very often.
