RE: Correct spine stiffness for X-heavy bows
 

Well, all I can say about what the guy is telling you is...."whatever..." I would think the people that publish the charts would know what they are talking about. But cutting them down to 29" would make them stiffer, so that may work as well. But I ASSURE you @ 31" a 340 is NOT stiff enough.

OK, since you didn't do the paper tuning, your results will be different because you are a different shooter. It's the same as letting someone else sight in your deer rifle for you. It just don't work. So you are going to need to be the one shooting it while paper tuning.