I handled the weight issue with fishing weights with a loop of fishing line. A strip velcro (hook) along the top of the counterweight stem, behind the main counterweight, keeps em from moving, a little experimentation and you will find the right amount of weight, then adjust the position of the main cw for your required vtf.
By the way, these are the same type of fishing weights I used for the Twl mod on my Rb 300.
Good luck Frank, Would post a pic but dont know how:(