>>37349175HM slave. At least then you can swap out party members and still train 6 mons at full potential. If you cuck them with HM moves, you won't be able to get rid of them until near the end of the game because that's where they always fucking put the move deletor.
Also even if you spread HM moves around your team, think about it. Are you going to have a water pokemon on your team know surf, dive, and waterfall all together? Are you going to have two water types in your 6-mon party just for all those water HMs?