I've only done the research on the WD45 clutch, not gotten my hands greasy... yet. I'm told that you can get the engine out without removing either rail or the front end. Remove the radiator and there should be just enough room to slide the engine forward to clear the clutch housing with a twist and a roll here and there.
The hydraulic seal is the reason I'm considering pulling the engine, but she's running too sweet to mess thing up yet. Until then, a couple of washers between the clutch housing and access plate to let the oil drain out, with a bucket under the tractor to trap the dribbles since kitty litter can't handle the volume. (I've cristened the bucket 'The Val-dez III' for the number of times I've forgotten to pull it out before driving off.) One of these days, I'll replace that seal... and the clutch... and rebuild the engine... just not yet.