My son, when he was playing guitar in a 'gypsy dub' eleven-piece, was using heavy gauge flatwounds on an Epiphone Casino and on a Fender Thinline Jaguar - either Rotosound Top Tapes (cheap) or Thomastiks or Pyramid Golds (both expensive). But he was not bending notes and was more doing rhythm skanking and clean melody lines. He did have a very thick warm tone.
I've also played with slide guitarists using flatwounds for a smoother sound.