As for separating, I think the main thing to be careful of is that the countertop is not restrained from expanding/contracting across the grain. Ensure that the front screws are through slotted or oversized holes and not crazy tight. Of course you also want to be sure you don't have one side drying or absorbing much faster than the other side to prevent cupping which theoretically could separate the wood if it's really bad. But I would guess the screws holding it down will help as well.
I do have a very cheap edge glued pine as a door to the electrical cabinet, finished one side only, and it did cup a bit the first trip or two, before straightening out again on it's own. It's been fine ever since.