You do not want ANY part of the smoke resistor to contact the side of the reservoir!!!! That will damage the PS/3 board in a heartbeat! NOTHING can be grounded for PS/2 or PS/3 except the input power connection. Lights, smoke, motors, are all totally isolated from frame ground. If they're not, you will be buying a new board, or at least paying for a component repair if you're lucky and it only takes out the driver for the smoke unit.
FWIW, that tiny rubber gasket isn't available either, so you'll have to make one of those.