My 12's on a 254mm wide board at +15/-15 work fine. Not sure how wide the artifact is, I'm guessing its in the low 250's. If that's the case you should be ok as long as you're not looking to do any shoulder-to-snow carves on bulletproof terrain (which I think it's a safe assumption this isnt the case, being that you're getting an artifact).
East Coast Park Rat
2008 Burton Twin 157 w/ Rome 390 Boss
2005 Burton Canyon 168 w/ Ride LS
"its ppl like you, that I would "impact damage" your face if i ever saw you
keep your mouth shut. one more time, please and thank you." -user: chingy_