Well in case anyone is following along.

The ZDZ 50ND engine requires about 2 3/16" inches of spacer/standoffs to give me the thrust washer distance stated in the manual.

I'm a bit worried about having the engine out so far supported by the standoffs... finding long enough bolts was a pain as well. I ended up having to take the bolts out of drywall toggle bolts, as these were the only things I could find that were long enough to do the job.

10-24 x 3" were all I could find in any hardware store. 12-24 x3 would have been better, but I was unable to find anything long enough.

While I have aluminum standoffs that I can combine to give me the required length, I'm considering instead cutting dowel stock to size.

The dowel stock is thicker than the aluminum standoffs. It may not look as nice, but there may be less chance of any lever moment effects breaking or bending the entire setup.

Anyone have any comments about using such long mounts?