Oh I didn't know they made one for the stock tank, new of the others. Just looked on their site and saw it your right. Derrick responds to emails well, you might email him with your plans.
Also, I have siliconed an Eva block to my hull to keep my aftermarket tank from sliding left. My water box is real wide, mounted in the stock SJ battery location so the tank can't sit where it's designed to sit and slides slightly left a tad, doesn't hurt a thing but I prefer it to stay planted.
You might want to use some Eva block in key areas to keep the tank from sliding. I have some extra block, it's the grey stuff that came in a shipping container. If you pm me your address I'll ship you some if you think you'll need it.
My hull had a stock SJ tank when hull was built, no Eva block was used, the hulls tank anchore were placed real close to the tank. If the tank moved it was stopped by the anchores. If I had concern of tank rub on the hook I put a small peice of turf on tank to protect it.