I'd suggest trimming the excess off with scissors or beard trimmer first, then the R41. The open comb deals better with thick hair, and does not clog so easily. For prep, a warm shower (not too hot) and something like Noxeema, Prep, or Proraso pre-shave rubbed in and left on for a few minutes. Rinse and apply your favorite lather from cream or soap.
Well it can be done with a DE, even without trimming: