I've been practicing butt wraps on my trusty ol' dowel, and I've been pretty satisfied with the results (so far just trying to copy the wraps on a few rods I have - I'm anxious to see what's in Tom's book).

I do well with single thread and with bands of nylon (only tried up to 4 threads), but bands of metallic are significantly harder to keep from twisting. Are there any tricks, or should I just stick to single thread with the metallics?

Laying down mutiple strands of metallic is not really too hard. Here is what I do.

The number of strands you can do, is pretty much unlimited. I would start with 4 or six until you get the hang of it.

1. Cut the strands the length you need plus about 4 inches.
2. Tape the strands to your work bench on one end and then pull tight and tape the other ends to the bench. They should be tight like like guitar strings.
3. Pinch the strands together on one end as compact as they would be on the wrap and tape them to the bench. Now it looks like a leaf rake. Bunched up tighly side by side at one end and still fanned out at the other end.
4. Pinch the other end together and tape them down to the bench.
5. Now, pull the first piece of tape up and double the threads back over the second piece and tape down on top of that piece. Trim the remainder. This secures the threads. Do the same thing at the other end. This will leave you with a nice group of threads and two handles to hold them by. Tape one end to the blank to start your wrap. Hold the thread with fairly firm pressure at all times. If you get slack in them you will have a devil of a time getting them back in the right order again.
6. Wrap on ...!

Hope this helps!

Worked like a charm. Thanks for the help!