Carbon spine help for long draw 31.5"

[7 Lakes]

I need some help. I bought carbon shafts when they first came out and swore I'd never buy them again.  But it seems they are much better these days and a customer needs a bit of help.  

He will be shooting a Fiberglass 68" moderate reflex/deflex longbow cut to 1/8" from center.  Maybe a tad closer to center.  The bow is 68" 56# @ 31.5".  Shooting 125gr. heads, fast flight string with beaver balls.  

He has both 400 & 500 shafts at 32".  Will either of these work for him.  Is he in the ball park.

[katman]

My thoughts are the 400 might work with bow specs listed but lean towards 340 spine.

[Matt Quick]

I would try the 500's first. With the bow not being cut past center will make a big difference. I'm shooting 500's with 250 up front out of a 64# great northern that's not cut to center. My draw length is 27".  So with a 31" draw I think he'll be close with 500's at only 56 lbs.

[hybridbow hunter]

500 should be fine