Stock 215 injectors are 5x.0105, 5x11 isn't much of a change, when I talked to Will about my tow rig 5x11's where never mentioned, but it may have been that I needed 155* spray for the first gen pistons I'm running and they don't offer 5x11's in 155*.
Have 1100 miles on this fresh build, 215 pump, 3k gsk, 5x12's, AFC Live, Colt S3, 300S 57mm, Engine makes lots of torque and pulls harder than the 6.0 so I'm happy with whatever power it's it, guessing 325-350. 800 miles have been towing tandem dully trailer hauling 10-16k lbs + 6400 lb trailer weight.
Average mpg is down a little over the old 160 with 5x10's and 10 plate but truck has a lot more power and towing average is higher.
Old average was 14mpg, 95% local roads, 50% towing with 50% empty trailer, 50% loaded.
1100 miles on new engine averaging 11 mpg, 100% local, 75% towing with 40% empty trailer, 60% loaded. Truck was down all summer and I was behind on getting farm products hauled.
I think mpg average will increase when towing average gets closer to 50%, PDD has also sent a different spring for the afc to see if it will help with the fueling curve, just need time to put it in.
My suggestion is go with 5x12's, you can always dial it back a little, with 5x11's if you come up a little short :banghead: