I had a harbercraft adventurer as my first “serious” boat and I often regret getting rid of it. Very similar specs to what you are building: was a 12-deg hull with a delta pad and 16’8” loa, so a bit shorter, powered by a 60hp Merc. Loved that little 4-stroke merc .... most of the time. Sipped fuel, super reliable and trolled right down to Kokanee trolling speed. However, it was under powered and I would say significantly under powered w/ three or more guys in it Fishing. Was most noticeable getting up on step, we had to make sure we got everybody forward , which will be a key consideration for you w/ a tiller boat. The 17’ adventurer was rated to 75 while the 19’ version was rated to 90, I definitely would have repowered with full hp but was happy living w/ the 60. Did make me a bit nervous fishing out of Ukee as I really had to be on the throttle running in swell as it wanted to bog down or sprint ... constant feathering to keep it in the sweet spot.
Beauty design and I love the concept, easy to trailer, use on lakes, bays or, on good days, the ocean, launch/run solo, cheap on gas, etc, etc. Will be watching as it progresses.
Cheers!
Ukee