I gotcha
These are similar to the type I use for shimming
http://www.lalocksmithsupply.com/Tools/ ... -pack.htmlhttp://www.majormfg.com/pc-303-60-curve ... stock.aspxand they work very well,
Usually I use a pick to manipulate the pins while I am shimming rather than a key blank. If I am having difficulties, or if there is spool pins, I will use the pick to lick the pins all the way up before I begin to shim. After shimming a couple of pins, if it stops or becomes difficult, I will back up the shim about half of a pins width, so that you don't lose the pin(s) you have already shimmed, but so that the shim is not jamming up against the pin you are trying to shim. Then lift up all the way up the pin not behaving, ease the shim against it, and slowly lower the pin til it catches.
I usually use the pick because I find it easier due to always using that method, but sometimes when it is giving problems, I will use a key blank. Often enough it goes smooth from there.
Also, if the lock is still being very difficult to shim, pour some lubricant in there to allow the shim to glide a bit better and to wash out any obstructions.