Thank you, RedPhantom and Glitteraty. I'll definitively try both ways. In my present case, I can't turn the lights much higher without overexposing the skin - I'm using Tempesta's Mina, which is very light. But for future images I'll remember this. For now I do get better results with indeed turning up the subsurface samples. If it's usually lightning that's causing the grain, then perhaps it's due to the fact that I've never used area light much (because of many outdoor scenes) but the Superfly studio consists mainly of area lights as far as I see. That's a sweet render, btw!