I'm looking for suggestions on a good rule of thumb regarding bike size. I'm looking at either getting a Giant Escape or Trek 7.2. The problem I'm having is at 6'3" I'm in between LG and xlg. I've been on both and the xlg, with.a longer top tube forces me to lean farther forward which I'm concerned will be uncomfortable for longer rides. However on the large it seems I have to bring the seatpost up a lot to get the right fitment. I've read that its best to go with the smaller size and adjust up instead of getting the larger and not being able to adjust down. Just wondered what the more experienced crowd thinks.

Welcome to Bike Forums! Sizing is tough without seeing you on the bike. Honestly, go with what's more comfortable. Forget what you've read, and buy the bike that feels better.