When you say gale sail, I assume you are referring to the storm sail of that name that fastens around a furled genoa/jib and is hoisted with a separate halyard using the rolled genoa as the stay.
Though there are some clear advantages to a hanked on jib
on a separate forestay if you have somewhere suitable to mount it, you might want to balance the tradeoffs of convenience and effort a little differently and go with a gale sail. When you don't need it, the gale sail is certainly easier to store than the additional forestay.
I have a gale sail on my cat as a storm sail, but have only rigged it in benign conditions so far so can't say how well it will really work in nasty weather
, but from it's design I'd say there is a good chance. Remember that whatever you are rigging
in those conditions, you do have the advantage of a large level platform to work from.