Thanks for that^ It pretty much tallies with my experience.
I found the OE TRP pads pretty poor on the stock 160mm front disc. Sintered pads (Nukeproof IIRC) worked better, but honked like a donkey all the time. Shimano organic pads were OK, Swisstop green the best. Even so, IME, the brakes weren’t very good. Initial bite was OK, but the ultimate power wasn’t there – I could be squeezing the lever (4700) until my knuckles were white, but not stopping any quicker (lever feel was OK).
I changed to an ugly, old style Deore 180mm disc on the front (to match the track width of the pads) and it is so much better – for the first time I feel that the brake generates enough power, and have stopped looking wistfully at hydraulics (this is using Shimano organic pads). I can get the brake to honk by using a certain pressure on the lever, but it’s not too hard to avoid this in day to day use.
The filing thing means that I should be able to use a nicer, lighter 180mm SLX disc that I have – thanks 🙂
The 140mm disc / OE pads have been fine on the rear.