I have a Dracos barrel on my 6 Creed. Its a 22" 9 twist, but they claim that it behaves more like an 8 twist. At 2900fps I don't have a problem stabilizing the 105's. I have also been curious about the 115dtacs as well.243 is a hard thing to find in an LR308 build honestly. 6.5 Creedmoor took over the world pretty much and 243 stuff went away by and large. That said the Midway barrel above was 8 twist. I would be hesitant to have a 10 twist unless factory ammo was a requirement. My Mcgowen barrel was something like $250 on a Black Friday deal and $300 without flutes now. Well worth the cost to get what I actually wanted. Next one will be fluted, 20", 7 or 7.5 twist and +2 gas I think.
As a question to the others here who have had it, what's the heaviest weight you've gotten away with at 1:8? I am shooting 105s right now but haven't taken them to a decent length range, nor have I tested heavier. I was tempted to grab some of the 115 DTACs that seem to be sprouting up for sale in the PX to play around with but an not confident they'd stabilize especially in the short length 18" barrel. I think I'd wind up down about 225 FPS compared to a 24" barrel based on what I've seen online and I just don't think that's enough spin to give the super heavy bullets a fighting chance although I'm open to being told otherwise.
From everything I've read people run a 7.5 at minimum for the 115s. That being said, I remember reading an article from Dave Tubb himself saying an 8 twist will work. I believe it was on 6mmbr.com if I was more savvy on snipershide.com I could attach the link.