The 8 twist is right on the verge of stabilizing the 115s, some barrels will some will not. I had one 8 twist pac-nor that would stabilize the 115s at around 3100, and have a buddy shooting them in his f-class rifle with an 8. To be safe I would use a 7.5 for 115s or the new 111s, but since you already have an 8 I would just try the 115s and see.
If you do not have any I would be glad to mail you a few to try, if you do not mind shooting moly, you might get lucky. I know I had about 15 left in a box of 500 when I loaded up for my last match. I could probably scrounge up a few more 115 dtacs from other boxes. They are yours if you want them. PM me an address and I will mail them to you. I probably have a few of an old lot of the bergers also. I dont mix lot numbers when loading for matches so I end up with a few strays that will gather dust.
BTW I do not think you can go wrong with the 105 bergers, they shoot very very well if you find the right lots.
I admit that I know just enough to be dangerous.....but dangerous at ever extending distances.