I would recommend aluminum, though there is nothing wrong with the other methods mentioned. If/when you have a bushing made, have them size the length of the bushing to be around .030" more or less shorter than the thickness of your favorite props. That way, the bushing centers the prop, but does not interfere with the clamping force/compression of the prop hub.

If your needed dimensions are going to result in a very thin walled bushing, the brass tubing method might be best. Or, to be able to use a thicker walled aluminum or brass bushing, you could use a prop reamer to enlarge your prop center hole.

There's nearly always "more than one way to skin a cat" if you are willing to "think outside the box."

By the way, the better equipped Ace Hardware stores have bushings and spacers made of plastic and aluminum that are often handy, and can be modified if/as necessary for the intended task.

AV8TOR