My Kodiak Hunter is 47@30 and shoots a full length 2016 w 145 head much better than a Gold Tip 5575 w 200 up front enen though GT is a better spine match, what gives?

I would say the 2016 is the better match if it shoots better.

your release, grip, rest, etc. all have an effect on the dynamic spine.  bareshaft tuning doesn't lie, it will tell you what arrow is needed.  if the 2016 shoots great than go with it!

Regardless of what the charts say the best spine match is the arrow that simply shoots the best. As long as broadhead shoot the same as your practice points you are good to go.

With regards to spine ALWAYS listen to what the bow says, it won't lie about which arrow it likes best.

I just switched to a weaker spine as well and the difference in the way they shoot is amazing. I get better penetration with the weaker spine even though it's a little lighter. I had the 5575 because that's what the GT chart showed but the 3555s shoot a lot better.

I'm finding this out as well shooting 54# @ 26" a full length 35/55 with 225 grains up front shoots perfect bareshaft at 20 yards, all the charts say that a 28" .400 spine with that much weight should spine good but bareshaft shows it to be stiff no matter how much weight I put out front.

Center shot plus or minus makes a BIG diffrence in the spine selection.

It is endlessly amazing to me how shaft manufacturers seem to recommend one to two spine groups to heavy for trad bows.  The local shop does it too.   They don't seem to understand trad bows at all.

Difference in sidecut is about 5#/16-quite a bit considering the different riser cuts and variety of sidewall material.