If you are drawing an honest 30" with a 55#@28" bow, your actual draw weight is probably in the area of 59#-61#.
As you have them, you might as well continue bare shafting a CX 4560 with your chosen 125 grain point. Remember you will need 3/4" plus longer than you draw for safety.
You know already know it spines weak at 33", so cut off an inch, rei-install the insert & point, and try it. If it doesn't fly straight to your POA (point of aim), remove the insert, cut of 1/4", re-install insert, and repeat. It might straighten up & fly right at around 31", but probably not.
If not, move to a CX 6075, start with a 33" arrow, and repeat. I'm guessing a 6075 will tune for you around 32".
If you like alums, try a 2216, 2413, or on the heavier spined side maybe a 2219 or 2315, and do the same thing. I will guess you will find find your tune around 31"-32" with the lighter spined shafts.
I shoot both alum and carbon, but prefer alums as they are not as broadly spined as carbons (makes for easier tuning IMO) and much easier to build & work with. The guys who prefer carbons do so mainly due to their toughness.
The heavier the point, the less spine your shaft has, BTW. If you want to shoot a 33" 6075, you probably have to go to a 150 grain+ point to get a tune, for example...
Just as an example/FYI, all my bows are 50#-55# and I draw 28.5". With 125 grain point/insert I shoot 30" 2117's or 2314's with all. Both tune nicely at that length and duplicate POI (point of impact) a 29.5" CX Terminator 4560 tunes out, but has a higher POI than the alums. I can/do shoot 30" 2413's but they spine a smidge heavy. It's close enough that once fletched they shoot fine, particularly with broadheads.
Good luck and have fun with it...