I would think it would be not be the best idea. It would probably cause some mast compression. Think about how much the mast flexes if you really pull down on the main halyard to uncleat it from the hook at the top.

I regularly raise mine while floating. It gets easier with practice. Turn it up into the wind and you almost have to plan in advance what side everything is going to be on. I'm light so I'll walk out on the hull and cleat it.