drains are definitely an issue to think about. In your case, if you are always lucky and never get caught out in really nasty weather
it might never be a problem. BUT, if you do get pooped you might flood the engine, short the starter, fill the bilge
and, if the cover is not secured and washes away, sink the boat.
I would do three things.
First, make sure that the cover is or can be secured by some sort of latch and not just held in by gravity.
Then, put some sort of gasket
around the edge of the cover (thick neoprene, hi density foam, etc) so water
in the cockpit doesn't all end up in the engine room.
Last, make sure you have adequate cockpit drains so if you do fill the cockpit it can go away quickly.