Sinkler's scrummaging is fine. He's generally solid at international level, with only the boks really hurting him, and lets be honest, who don't they hurt?
As for his temperament, the only time I can think of him losing it was when Cowan Dickie flew in and smashed his knees with a LCD special. Fairly sure a few on here have had issue with those low grasscutter tackles before too. He's similar to Genge, right on the edge, but rarely over. Again, plenty saying they want a bit of nasty in the pack, well that's as close as you can get these days.