New arrow tuning question

[Buschlatte]

Guys, I'm green so take it easy on me.
I currently shoot a 55lb bow at 28. Drawing 29. I'm shooting carbon legacy 340 at 30.5", 100 grain insert, 150 grain head. Arrows fly great out of the bow.
They are 10.1 gpi.
I recently ordered a dozen uncut bloodsport Timberwolf arrows. They are 350 spine. I plan on using the same inserts and heads. Something I should have paid attention to was the 7.9 gpi. Before I get to cutting on these arrows, are you thinking I'll need to have them longer, shorter, the same? I'm thinking that spine is spine, but is this difference in gpi going to change this arrow flight?

To be clear, I'm not the greatest shooter out there. I'm proud of it, but I know my place. I just need this setup to be able to fly some 150 gr magnus heads comparable to my carbon legacys and I'm looking for insight on a starting point. Having to cut arrows multiple times involves me having to run to the shop since I don't have a carbon cutter at home. I'm trying to avoid multiple trips. Thanks

[Buschlatte]

Trying to find the delete button because my post is null and void. I threw an insert in an uncut arrow and they fly better than my current setup. Sorry for the dumb post.

[Orion]

Not a dumb post.  Of course, spinewise, the arrows are very close.  I assume they're also the same diameter.  All other things being equal, because they are physically lighter (it takes less energy to get them going, or put another way, the same amount of energy will move them faster) you would likely need to come down in point weight a little, or leave them a little longer.

However, because they fly as good or better than your original arrows, it just shows that you were probably on the heavy side of tune with your original arrows, and are even better matched now. Good for you.  

[Buschlatte]

Orion, spot on I think. With these arrows being uncut they are around an inch longer. I can tell this arrow is flying a bit flatter but they are absolute darts coming out of this bow! Really excited about it. I just need to find some more hot melt and get these inserts in and I'll be fully up and running.
Thanks for the reply