Got something to share after some research on belts.
Various RC belts and number of teeth for cross use / reference. I hope my work can be use for all of us.
BELT(T)........NT1........MTX4.......MTX3.......V1 RRR.......MRX4.......M3........G4S
FRONT..........62T........63T..........67T........ .63T............67T..........69T.......70T
MIDDLE. ......132T......129T.......125T........128T....... ...144T........140T......126T
REAR............59T........59T.........64T........ ..60T............67T..........67T........64T
Most RC belts are 3mm pitch belt.
The length of RC belts = total # teeth X 3mm
Examples : Evolva M3 middle belt is coded S3M420, S3M means 3mm pitch, 420 means 420 / 3 = 140 teeth.
Notes : Evolva M3 and MOTONICA P8 have same number of teeth.