Thread lock actually works just like grease for this purpose, just not slippery. It insulates between the two types of metal and seals out ant contaminants. Use locktite blue and you will be able to get these screws out down the road. If you don't you will experience titanium "galling" where a tiny bit of bionic corrosion forms and the two pieces of metal will be together forever. This was a common problem with Titanium bicycles. Water bottle screws, bottom bracket threads and seat posts would all get stuck, usually permanently. This all ended when we began using anti sieze compound.