I see you.
I suffered the exact same issue (nearly slung them) until I discovered the joy of KY jelly!
As others have said, it’s ALL about ‘seating that bead’ (walk away from the metaphor).
I’m currently running the same tyre combo and I’m not shy with the Peaks rock gardens either…no problems at all since adopting following method..
1. Ensure the rims bead is clean from crap/stans etc
2. Run a little KY with finger tips round tyres bead
3. Add a couple of caps worth of Stans for taste
4. Lift wheel from floor, blast up to 50psi with track pump
5. Spin, angle, spin
6. Leave for ‘a while’?? (I usually go for overnight)
7. Deflate to working psi
Like I said, exact same happened to me…I actually dinked my front rim a little ….bit of a pisser but they’re tops now and yep, ZERO pinch flats or thorns hereon in….a new day, a new dawn brother 🙂
One thing I’ve noticed is that tubeless tyres indeed deform differently than tube types. Insomuch as they don’t share the same psi to deformity ratio…clear as mud that 🙂 That is to say if your rear ‘tubed’ set is running at 20, then (for my set up anyway, can’t speak for other tyres) I’m put 30 in the tubeless set due to their apparently lower ‘squish’ co-efficient…I’ll leave it there before I receive a kicking.
Stick with it, if your in the Sheffield area then I’ll help if you wish?