Striker,
The UCD that I have, like MANY of them, had NO right thrust built into the firewall, a simple check with a carpenters square will show the firewall to be at 90 degrees to the fuse sides.

After flying mine I determined that the plane needs about 3 degrees of right thrust to fly strait uplines. I wound up putting 3 washers under the left side mount to space it out from the firewall. Doing this really shifts the spinner to the right and it doesn't look to good but I will take a better flying plane over a better looking one any day. I had to take some out of the nose ring of the cown to clear the engine thrust washer to be able to put my cowl back on, when it's all done I think my spinner is offset about 1/4 - 3/8" from the cowl.

The best thing to do is to fly it and then adjust to your taste. Fly it with the cowl off and pull up vertical, go to full throttle and observe. If it pulls left start shimming the mount. Your definately going to want to do this before attempting to hover this plane, it's a handfull if you don't.