A 10g is pretty small for active 3-4 inch fish. I did it for a while but felt it was too small long term. They were young, smaller loaches that liked to hang out in plants at the top. That used to scare me! It got so I could even reach in without them moving.
I had both striped & black pangios. I'd had the striped for 4 or 5 years & they were more sedate, more people friendly. Then I added black ones that were much more active especially after water changes. I thought they might calm down & they did a bit, but even after a year or 2 I worried they'd "loachy dance" right out of a 40g long rimless. The 2 species did not hang out together much except at feeding time. So I'd say, based on fish I had, I prefer striped for looks & "personality" but enjoyed both. It's interesting your lfs said striped are more popular, I was told at a big box blacks are more hardy so that's what they get but never sell very well.
I don't think I'd keep them in less than a 20g long in a group of at least 6. I saw you have several tanks, could you move them if, like I did, you find a 10g too small? There are a few very small loaches that might work better in a 10g, I have/had rosy loaches & "Vietnamese multi-striped". Neither are super common but are available (or were) online or maybe lfs can order for you.