Keep in mind or if you weren’t aware, the ‘70s 170 is very weight sensitive a stern. I’d expect porpoise issues unless you’re considering a 4-5ft tiller extension to position you further aft and stowing the fuel tank aft. Trim tabs resolves that issue, except you won’t have a console to mount the tab controls. What I’m getting at is….standing stern along with stowing fuel tank at stern will likely present hull performance issues.