Viking
I shoot 55/75's and use the 15 gr.(silver) insert...on the Gold Tip site, using the FOC Calculator, it's listed as "insert .246". I've been shooting Gold Tip's for 5 years and both bow shops I've had arrows made up at have used the same insert. I noticed one of the inserts they list is like 47 gr<img src=icon_smile_shock.gif border=0 align=middle>....wonder what kind of arrow that would be used in? Hope you get it worked out.
TB