According to Mule Deer's 1/4 rule, the 270 SPR should be capable of around 200 fps increase at similar pressure levels compared to the 6.8 SPC. This is using the case capacity figures you quoted.
According to Hodgdon 6.8 data, a 110 Vmax is capable of 2690 fps with a 24" barrel (with 30 grains of IMR 8208) . Conservatively estimating a 15 fps loss per inch, that will be around 2610 with an 18" barrel at similar pressure levels.
So if your round is capable of a 200 fps increase, we are looking at just over 2800 fps with 110s at similar pressure levels.
This is if everything goes according to plan. The increase in case capacity may bump up the best powder choice into a slower bracket, and IMR 8208 may not be ideal. In face, I'm betting it will be on the fast side when it comes to 130 grain bullets, but that's just a postulation.
Try using the 270WIN as your base starting place and work down vs using the 6.8SPC and working up and lets see what that shows. I would but i don't have that QL software yet.
