Ideally if you want full range I seem to recall you should have at least 1 sampled note per octave, though I'm pretty sure the 2hp won't accept multi-samples. So if you keep your playing range within 8 notes each side of middle C you'll be about OK.
I once sampled each note of a Roland MC-202, editing each for sustain loops, and put them into a Reason software sampler, that was very boring workflow!
Enjoy your spare HP, don't rush to fill every last space, this is not like filling sticker books. Resist the urge to 'complete' your rack, its never complete so just relax.