About the spools.
I have been under the same problem, last nacional championship race I had to tight it every final.
I believe I must change the plastic parts and try again. The feeling i have is that if I hold the left wheel and the pulley and turn on the right wheel this will tight it, but that means that under braking turning to the left it will make the spool loose.
I will let you kown if I can go over this.