Hi Ron ... I enjoyed your post! Welcome aboard, and let us know if you have any questions along the way.
I like your family-oriented approach .. I know of cases where kids and wives got neglected 'for the temporary boat build' and divorces occurred. Glad to see you are taking the opposite approach and wanting to make it into a memory and relationship thing instead of a "gotta get it done and go fishing ... at any cost!" project. That's fine for the single blokes out there, but families warrant special consideration.
I would say ... start as soon as you're comfortable. Make it the 'experience' and 'memory' thing with the family and don't worry about when it gets in the water. I might try to set an outside completion date as being before the "kids are out and gone, and can't remember who their dear ol' dad is".
Re your 6' 10" height ... if it were me, I'd keep the pilothouse deck right on the stringers (gives 6'4" headroom) but then raise the pilot house roof 6+ inches to get at least 6'10" headroom ... and add a bulwark on the f'w'd 2/3rds of the hull to help keep the aesthetics in proportion. Go ahead and raise the cockpit sole for more under-deck room and better self-bailing characteristics if you want, but provide a sill at the bottom of the house door to prevent water draining into the pilothouse - since the interior deck is now lower. Otherwise, go at it and make it yours!
Brian