may stay dry even if you swim for a bit. But I would prefer to rely on my roll.
If you use a drytop, I recommend that your skirt tunnel be a bit looser, so you're not fighting it with torso rotation. *Also* if you find you have to roll down the top of the skirt to fit the drytop, trim off the top of the skirt accordingly.
URCHIN Portable Anchor
Kayak Motor Kit
Wabakimi Canoe Pack