[Skruface]

I have smooth gearsets. They have no shims at all..never have had shims, even on the older "non-smooth" sets. It's the frame itself that keeps the gears properly spaced. Once you get them sealed up inside the mechbox there will be less play. If it really bugs you, use a slightly thicker oring on the outside of the bushings (if you look close, on one side of the gears there is a small rubber o-ring around each bushing) to take up the slack inside the mechbox.

As far as the tool goes, when I got my gears (through Airsoftparts.ca) it came with a little gear key....it is identical to the larger Modify key "required" for disassembly, so you only need another one of these to remove the gears, as the axle is threaded on both ends. Be aware that the little "nuts" you need to undo with the key have some kind of threadlocking compound on them....I had one shaft that had the nut on so tight that I had to remove the bushing, wrap the axle shaft in rubber and then lock it into a pair of vicegrips so I could get the torque to undo the nut. On the plus side, the axles are definitely machined steel....I used a variety of pliers on numerous attempts right on the bare axle shaft (with no rubber covering) to try to remove that stuck nut and it didn't even leave a scratch or indentation on it.