I loved my '75 18SF, and miss it still
I went with a Birdsall leaning post & a brand new Zuke DF140 (back in '02), and while it weighed in at 410 lbs, it was/is a very sweet combo. Moved the batteries under the console front seat and tried to keep as much weight forward as possible when underway. Went with a big bimini instead of a t-top, 'cause I liked running early morning/evening/at night with "the top down," but in the middle of the day enjoyed a lot of shade. I tested a few wheels and propped for best mid range performance to optimize manuevering in dicey sea conditions rather than hole shot or WOT/top end. Kind of like skiing moguls, steering around those big blue-green bumps! I checked several times and after a full day's running, idling, trolling, cruise & bursts of WOT (42+) she averaged out around 5mpg for the day - still makes me smile! I agree that trim tabs would be a good addition, as quartering seas can make for a wet ride, and would help keeping the bow in the water.