Been running a similar project on my Scott Spark. You are safe with titanium bolts anywhere on a mountain bike IMHO. But before going that route, there is a better bang for the buck in terms of weight savings before you drop 100$ to gain 20 grams. A good place to start is checking R2 Bikes in Germany
https://r2-bike.com/. They weigh almost everything they sell, and you can list items by weight. I have already taken the bike from 12.45 kilos to 11 including a telescopic seat post that adds like 400 grams. And that without spending too much. Some examples below:
- Wheels: ZTR Crest rims are at the lightest end, with reasonable strength and a pretty decent price. I am running them with DT 350 hubs (no point in going 240 in my opinion)
- Tires: running a Continental Race King saves me 400 grams over my current tires
- Cassette: Garbaruk makes very good light weight cassettes at a fraction of Shimano or Sram prices. You can even go 12 speed on standard shimano hubs, only it will be 11-52 instead of 10-50.
- Pedal spindles: using titanium spindles can save you around 40 grams
- Disks: Ashima Ai2 are at the lightest end for very little money. I also found that at 74kg I can run 160 at the from which saves weight not only at the disk, but also lets you get rid of the spacer and use shorter bolts. This would be the time to add titanium bolts to the disk and the calipers.
Hope this helps with your project.You might want to check this crazy project taking light to the extreme:
https://www.pinkbike.com/...-lightest-29ers.html