Since I work at Cabela's, I get to play around with different gear.
I grabbed some 400's and 500's to in store use in the range. I bare-shafted both and they seem to be really nice arrows.
I bought a 1/2 dz for myself in 400 and 500. I shoot pretty light weight stuff, old Bears in the 30-45lb range, with B-50 strings.
For the most part, they seem a bit stiffer than I expected. Often, 500's are perfect out of a some of my 40lb Bears with 100 or 125grs up front. These 500's are going to require more weight, probably 150-ish. I'll play around more and let you know.
Keep in mind, I'm shooting old Bears, B-50 and I'm still not drawing back my 29" after having rotator cuff surgery last December. So the arrows are likely showing stiffer than would be in reality, when bare-shafting.