Ok guys, mentioned I was new to the trad bow arena and can use some input. Hoyt GM II  , 30" DL, 43 LBS. I looked at the 3 rivers site and used their chart to size some wood arrows and wonder if I can use 65-70 spine arrows with 145 or so up front and be in the ball park. Thanks for the advise and help.

I'd start with 2016 aluminum.

B

Start with Stu's Calculator.  Find the deflection and you can use that for any type arrow.

Bowmania

2 words--test kit

I'll second using Stu's calc first. It's pretty darn accurate and will save you a lot of frustration.