cvd's too short on my brushless

i found the solution to my problem, i have rpm shock towers and i just got my new flextek arms and also new 1/'8 shocks. now it came to me at the track the other night at the track, actually someone mentioned it so i cant take the credit for it really. there is no adjustment on the top of the shock tower, and only two on the new arms. what was happening was the shock was making the arm drop too much and therefore the cvd's were almost falling out. sssssoooooo all i have to do is put some spacers inside the shocks, problem solved. now all i have to do is work out what i use to make the spacers out of. ANY IDEAS.......