5' 11" 228 lbs - big?
Did you ever see Derek Hutchinson who founded the British Canoe Union and designed the P & H Serius which is a low volume boat with a small cockpit. You're not that big. Try some commercially made boats before you come to the conclusion that you need an expedition size boat. Your shoe size and height make it tougher to get into some kayaks more than a few extra lbs.

When you do make one - use or copy a cockpit size that's a standard so it's easy to get spray skirts for it.