Originally Posted by zz4gta
Thumbs, I don't think that'll work in his case, as he wants to use the winch after he cleats it off. So the cleat would need to be on the highly loaded side. I've had trouble un-cleating a cam cleat before in high winds, and I'm not sure that would be the answer if there's little to no purchase on the mainsheet (assuming there's not since its lead to a winch)
the mainsheet deserves its own winch...if the OP can't find an alternative to making a second use of the winch serving the mainsheet, then he should just release the mainsheet and luff the main until the sheet can be put back on the winch. Better to have it luffing occasionally over the years, then to not have it release instantly just once. Been there, done that...