Arrow spine help

[Flbowhunter]

Hey y'all, I need some help with the spine of some arrows I'm wanting to get for a new bow. The bow is a old mountain mesa rd longbow (cut 1/8" before center) #50@28. I draw ~30.25 I'd like to have about three hundred grains up front (100 grain brass insert+200 grain point). I know I'll need to bare shaft but if anyone could help me get in the ballpark I'd appreciate it.

[Orion]

Given that much weight up front, probably a .340 left full length.  A .400 might also work.

[Sojurn]

My bow is similar in wight to yours.  I shoot 300 up front and I'm shooting 400 spine standard diameter shafts, and 350 spine micro diameter's.

[Flbowhunter]

Thanks I have some 340s laying around I'll try and if they don't work I'll order up some 400s