Just for the sake of curiosity what bolts are you replacing and how much weight are you going to save? $70 does not buy very many Ti bolts.
Also what chain weight did you use in your calculations? When I converted from chain drive to the Gates belt the total weight reduction was 232 grams. I was using an 8 speed timing chain that weighed 426 grams, the new Gates belt weighed 108 grams.