Eric,
If he is using a Foredom with a 1/4" chuck I like the Kutzall taper 3/4" or the Typhoon taper in coarse, both with 1/4" shank. It's pretty much the only burr I use in the Foredom, except a ball for hollowing. If he is using a micro motor or for finer work I use a carbide 1/8" shank flame...