ORIGINAL: Roskoe
With 100 grain tips, and a 55 lb. draw weight at 30", you should be good with any Easton 400 series arrow. Going up to 60 lbs, with either the 100 or 125 grain head, is going to require the 340 series arrows at 30" length. The Axis ST would put you over 400 grains in total arrow weight, providing great accuracy and superior penetration.
I would have to check OnTarget again, but the problem with the 100gr tips was that the FOC was lower than I wanted (probably in the 8-9% neighborhood). The 125gr got the FOC up around 11%. I agree though, the 340 series is definitely the way to go for longer draw lengths and draw weights above 55lbs.