Razorcaps are silent for me but I also have the 125 snuffers with 75gr steel inserts inside and they fly quite too,,, only way to really tell I think is to have someone stand off to the side down at the target but I really havent done that yet.
finally I use the same bow and weight as you and my choice for hogs next month is STOS 145gr 2-blades with long 42gr adaptors--> dead quiet and fly perfect and with worn-in parabolics I doubt theres any hint of whats coming to whats on the revieving end with my heritage it totals 560grains total from a 50# recurve.