There is a sweet spot for sensitivity being between about 8-14 inchs. Bloodsire has said this, along with a few other people. If you take a look at any top level scout, their sensitivity is pretty much around the 11-12 inch range. I'm not saying you should copy them, but it's definitely something to look into, and if you're stuck for ideas I would suggest trying this out.
There are exceptions, such as b4nny, but you should base your sensitivity around what feels most comfortable, not what class you play. I personally play with an 11 inch 360 and can rocketjump and do 360's just fine. I'm also a scout/sniper main.
Edit: It seems other people have said this as well, I did not realize that. At the very least, I can emphasize their point.