Chain,
I'm not as familiar with GT spine charts as others. But I will tell you that most people here have experience with 27-28" draws and they tend to make recommendations based on their experience which simply doesn't translate to 31 or 32" arrows (as you said yours are uncut). Their intentions are good but they simply don't have the same frame of reference as someone like me who actually shoots longer arrows. Again, I'm not trying to disparage other people. But early on I got lots of advice from people who shoot 28" arrows and almost none of it was worth the time it took them to type it and it cost me some wasted time and money.
You can dramatically affect the dynamic spine of an arrow by cutting 1/2" off the length of a shaft. So those people shooting 28" shafts are doing so based on a significantly different dynamic spine than someone shooting the same shaft at 32" and their advice has to be interpreted through that lens. Problem is when you are new you don't get this.
So, my advice is to talk with a good trad archery retailer who knows his stuff. 3River and Kustom King here on this site are very good. Let them know how much you want your shafts to weigh, how long they need to be, and the type and poundage of your bow and ask them to make a recommendation. Also, ask your bowyer.
I had people on these forums telling me I should be shooting 500 spined shafts in my 55# bows with 225 grains up front and 31" shafts. Those shafts paper tuned so weak it was ridiculous and I ended up with .300s when it was all said and done. Might have worked for someone with a 28" arrow fine. But in my bows at my draw length they were like pushing a wet noodle. Again, all with good intentions but from a profoundly different set of physical paramaters to work around.
As an example, in my 66" ACS longbow, which pulls 57# at my 30" draw, I ended up with Easton .300 FMJ shafts 31 3/8" long with a 75 grain insert and 170 grain Aboyer broadheads. There are more than a few people here who would tell you I am way overspined for a 57# bow. Yet this is exactly the shaft recommended to me by the folks at ACS and the Easton chart! But an ACS longbow is a high performance bow compared to a Hill bow plus the shelf is cut past center which also makes a big difference. In a Hill bow using the same paramters I would probably end up dropping down to .340s or even .400 spined shafts to get good flight.
Personally, I figure out what broadhead I want to use first, the desired total weight of the arrow second, and then back into the kind of shafting and inserts that get me there with only small adjustments in shaft length etc.