Another Hugo inspired tip, regarding smoothing block restuffing.
Rather than using a pipe-cutter, you can use a file to partially remove the rolled seam at the base. You can then clamp the solder tags in a vice and pull the can off leaving the "gubbins" behind.
I have done this with several smoothing blocks, and when the paxolin is cemented back into place after reshuffling it's difficult to tell it's not original.
The 1mm drilled holes are so the new capacitor wires can covertly exit and connect to the solder tags.
If your smoother uses its can as the common ground, you also have to sneak an earth wire out.