[TowerTalk] silly guy preform dead end question...

[StellarCAT]

I have always used cable clamps ... but this time around the preforms were about as cheap as
 the cable clamps. I have researched here there and (most) everywhere but cannot find clear 
cut instructions on how to use these things. Is the guy simply cut and held straight and the preform 
simply wraps around it!? The guy could theoretically  "pull" put with enough force - i.e. it is not 
hooked/looped or anything else? 
[I know, like a Chinese finger lock that the more you pull the more they "grip"...BUT]

Is there any "magic" to it or any caveats? Both with the guys using thimbles (i have the right size 
thimbles) as well as around insulators?

thanks for any help.

Gary Myers
K9RX