14" is a little tight for my taste, but you should be fine as long as you do some sort of easement curve in and out of the 14". It will make your longer rolling stock look better going around the sharper curves and you'll have less issues with your equipment. I use 19" minimum on my home layout with easement curves and have no trouble with my full length passenger cars that have body mounted couplers. I've even had a buddy of mine run his 89' MT flats with body mounted couplers on it with no problems.
Nate
