Yes you can remove it no problem. You are correct in thinking that you have to plug the holes. Make sure you seal them holes good, and then its a good time to seal the rest of the mast.
You said you don't use it often, nobody uses it often, well I know a couple people who use it more than normal. But its that once in a while when you capsize when you really wish you had it.
I've sealed my entire mast rivets and all 'cept the area behind the sail track where the comptip joins with the stick. I'm considering popping out the track and sealing this area and was wondering if you guys did the same? I hate the thought of one potential leak in that critical mast/comp tip joint (although the yellow foam is supposedly seated in pretty far).
My mast seems to be pretty watertight. At least I think
so - I've had the boat on her side for upwards of 15-minutes without turtling and there doesn't seem to be any water sloshing around inside the mast.