What do you guys use for motor mount standoffs?

[Loneflier]

I'm building a balsa/ply E-Flite ARF Leader 480. It comes with four 18mm long standoffs designed for to fit the cowling with the 480 motor. I am planning to use a Power 10 instead, and really only need about 8 or 9mm standoffs due to the motor's extra length. However, I don't have a good way to cut the existing mounts so that they would all be precisely the same length. I could cobble together some washers and get there, or possibly cut some out of hardwood spar material and drill the holes for the screws, but I figured someone out there has done this before and might have some better alternatives or suggestions. I can order some from Horizon, they have 7mm standoffs for 11.99 set of four, but would like to find an alternative from someplace like Lowe's or Home Depot. Possibly some hard rubber grommets?

Ideas anyone?
Thanks,

Rich

[fhhuber]

My most common way is to build a box of lite plywood and then use threaded rod clear through the box and firewall. Cheap quick and easy.

[Loneflier]

Thanks fhhuber! I may end up doing exactly that. Since I only need about 8mm, the box would be pretty thin, but will see what thin plywood I have on hand.