In my humble opinion, hydromorphone is more or less a less-prickly morphine, whereas oxycodone has stimulant properties . . . it will be smoother and not as speedy.
Hydromorphone is a prototype of a group of morphine derivatives, the 14-dihydromorphinones & morphols, which includes oxymorphone, hydromorphinol, oxycodone, hydrocodone, thebacon &c though oxycodone is in a category of its own as potentially being a molecular speedball type set up. Then there is morphine itself and codeine, a third group is the morphine esters like nicomorphine and smack, fourth are the bridged oripavine derivatives like buprenorphine, the fifth is the DHC/DHM series, another is morphides, yet another is the morphazones . . . there is enough difference amongst them that the optimum is to have representatives of the first five available for medicinal use . . .
I suppose one could figure something like the following:
40 mg oxycodone PO = 50 mg morphine HCl PO = ~44 mg morphine base = 53 mg morphine sulphate
44 mg morphine HCl PO = 5.5-10 mg hydromorphone PO
10 mg hydromorphone HCl = 8.9 mg hydromorphone base
8.9 mg hydromorphone base PO = 1.18 mg hydromorphone base = 1.32 mg hydromorphone HCl IV/IM/SC
All three of those conversion ratios are the ones which are published in charts, but especially with the hydromorphone it may be necessary at the beginning to start at a conservative dose and hack out the de facto conversion ratio and write it down -- for example. the morphine:hydromorphone equalisation ratio can range from 4 to 10.
Insufflation must do much the same as sublingual administration -- you will get 30 per cent or more additional effect. See if dissolving them under the tongue works first before railing them . . . alternatively, get some distilled water or sterile saline, dissolve some tablets in it, and put it in a nasal spray bottle.