arrow selection question

[PA stickbow boy]

i need to make up some arrows for a maine moose hunt. i shoot a silvertip that's 58#@28 & i draw the 28inches... i want to go w/ a wood looking carbon. either the goldtips traditional or carbon express heritage.  my arrows would be 31" long.  i currently shoot gold tip hunters 5575's & they shoot good.  the 5575 traditionals are .400 spine & 9.8 grains/inch, the carbon express heritages shafts needed according to their chart is the 350's which are .320 spine & 12 grains/inch.  i'd like to go w/ the carbon express shafts & gain 68 grains just in the shaft.  my question is why is one a .400 spine & the other only a .320 spine? & does that make a difference?  oh, i'm adding the 100 grain brass inserts to which ever shaft i choose to get the weight up.

[vermonster13]

The .320 spine is the stiffer arrow. You need to tune them before you can decide a length and tip weight if you want the best flight possible. That takes some time and this is a good resource for doing it

 http://www.bowmaker.net/index2.htm

[Quinn]

I think the Heritage 250's will work well for you. I shoot them out of my Roy Hall takedown recurve, 65# @ my 29" draw length.
They're cut to 30 1/2" with 215gr up front. They're a bit light for the weight of the bow but I already had 'em & they shoot like darts.
I bet at 31" & maybe 250gr up front they'd work pretty sweet for you.