what would be the right way to go about making it a full stringer
Buy a full stringer boat....
But seriously, for the amount of money and time it would take to do a conversion, you could have upgraded to a better hull...Absolut huge amount of work, and truthfully, I would not recommend doing it unless the hull was obtained for say...Free and all of the wood needed to be replaced.
A reputable shop would charge in excess of $3500 for such an undertaking.
I am not using my boat this year, and maybe next (I have three boats

) If you want to go 80+, I have the hull for you. My White Trash has seen 85 MPH with approx.680 BBC horsepower, it weighs very little and has full mahogany stringers....It does get "light" and I have added a droop snoot to try and improve it. (it used to lift the tail)...
12JG, full droop, manual Diverter, SS "A" Impeller, tandem trailer and top secret loader among others, PM me if you are interested.

GT