Backplate is no problem, the headscrews I do not know, I do not think Titanium is the right material to tighten them a lot.

You wanna loose weight? The 1st thing is try to loose rotating mass, I already have lost 20 gram with the clutch and brakedisc and that is a lot that close to the source. 1 gram on the clutch is like 5 gram at the wheels