You have a rib. You can absolutely lift the bow by that bow fitting (you anchor the boat by it). Don't attach to the rope, attach the davit snap shackle to the fitting (metal to metal). Your aft attachment dimensions look about right to be able to bring the boat up against the davits, but I don't like the look of that knotted rope. Long term you want a wire harness (rigging shop) created from your experimental dimensions. What is that fore-aft line for?
Gunni, you talked me out of $82 for wire harnesses with rings on top for the davit shackle. Forward eye is far forward, under tube. Fore and aft line pulls attachment point out from under tube, and aft bridle out from under outboard lifting handle, so blocks and moving parts are vertical and run clear New rope will connect the rings to maintain present spacing of lift points.
With a 6 foot transom, bimini mount bars and a boarding ladder gap in the middle, I didn't have a lot of stern rail to choose from. Davits taper in slightly.