I've built the Tern 17' for myself and the Tern 14' for my partner, Barb.
At 220lbs and 6'1" the Tern 17' fits me great and there's enough reserve left for gear. The Tern 14' is definitely too small. All though it's quite comfortable with enough foot room for me, at my size it just sinks too far into the water. Barb is 130-135 and 5'7" and the Tern 14' fits her just perfectly. If you're in the Cleveland area, you're welcome to try both. Sounds like you're right in the middle.