Well i called Nosler today and they didn't have data but the nice fella there told me to just use data for the 270gr. Hornady, and that I could probably work up a little.
SSK, said they didn't have any data for the BT.
I feel quite confident in my data, but I am still going to back down a half a grain and call it done. I may give it back that extra half grain before hunting season (cooler weather, higher altitude, etc.) but until then by shoulder will thank be for saving it a little abuse!