I have tried lot of different overgrips. For me Wilson Pro White is the best. Some people say Tourna is the best in hot summer days (I do not know yet). You can order from TW different overgrips in small packs - do not order 30 grip roll if you have not tried. I was little bit disapointed with Tourna (maybe my expectations was too high):
1. Tourna overgrips are not cut in angle (both ends are cut 90 deg.).
2. It wears out fast - I change it after 3-4 hours.
3. Wilson has softer feel and more grip.
You should test and decide. Sure it is not bad overgrip - lot of Pro using it...
...yes, Tourna grip from TW comes 2 x 15 rolls