RulerofXbox, your best best is using the "Edit Coordinates" menu, which you can find by pressing B while holding the object in question.
This will snap the object to grid coordinates, which you can "fine" tune, though you may find the smallest adjustments possible in this fashion to be more than you want. Both objects in question can be snapped to the grid coordinates for easier alignment, but this leaves the rest of whatever structure you're working with at the mercy of potential gaps developing (albeit small ones, they're still annoyances to me personally). If you're not happy with this method, as I often found myself, you're stuck using the bumpers for vertical adjustment. Which, I'm sure you're already aware, is like trying to park an 18 wheeler on a space meant for a clown car.