Interesting combos. Always like to see what others are shooting. I shoot CX's. I started with 250's because Stu's calc. said I couldn't put enough weight as I wanted up front, but I have trouble with the calculator. I found that I can shoot the same weight combo up front with 150's and 250's if the 250's are 1.5" longer than the 150's. Whether your bow is center cut of not will also affect the arrow spine, so start long and shorten the shaft until you get the right length, no matter what shaft you end up trying.