Ok, rode in the HR Farm breeches for my lesson today. Also my first serious ride in my new, very grippy saddle, for my 4YOs second time in the outdoor since August. So a real test 
While I don’t think I like the silicone grip seat as much as traditional leather–and probably could get away with knee patch breeches in this particular saddle, honestly, and maybe I’d like it more if I was actually doing more sitting, rather than Intro on a baby–the breeches themselves were better than I expected for the price. I definitely like them better than my Pipers–they’re high enough rise I wasn’t worried about mooning anyone while putting on boots, and the material is sort of yoga-pantishly soft. I’d definitely recommend them to someone who likes the silicone fullseats.