With a 55#,at my draw, recurve,when I shoot a 400 spine arrow,I need app 250 grs on the front end.I have a 29" draw and arrow is 30".To go up to .340 spine,it takes 400 grs total,point and insert weight.
Adding 100 grs to the front end weakens the dynamic spine app 20#'s.
Your setup sounds stiff to me with a 27" arrow but only you can determine that by shooting.If you are truly getting good arrow flight now,I think you would need to go to .340's but I would be very cautious about cutting the shafts down too quickly.Start long and work down gradually,have a variety of heavy field points handy and be open minded about what weight broadhead you may end up needing.Your 125's may not be enough.
The other thing is,when you jump to a stiffer carbon spine group,expect the overall arrow weight to increase 120-150 grs(more point weight and slightly more shaft weight).That may be just
what you need or may be more than you want.
It is hard with carbons to predict and hit an exact overall arrow weight but if you get within 50 grs,I don't think you will visually notice any difference.