How are you applying the finish, Bill?
'Hand-rubbed' meaning cheesecloth or a rag is a pretty thin coat, so I wouldn't worry too much about loading it up that way. I use a foam brush, well wrung out, to apply the first few coats. After some build-up and curing happens, (you can hasten this with a lamp and fan) I will buff with 0000 steel wool, then apply a couple hand-rubbed coats with a roll of cheesecloth. Circular motions. This kinda' softens those coats underneath, so don't get too forceful. No personal experience with buckeye, but walnut burl definitely soaks for a while.
I love a tung oil finish too. Me and Dad have used it on our banjos for years for a more rustic, natural feel. Wood is funny... some of it will soak that stuff like a sponge, some of it a couple coats is plenty.
Here's a 'pony-scale' five string conversion we did on a Gibson TB-2... I finished the neck and resonator in tung oil. There is a thin coat of alcohol-based tint to match that mysterious dark purple varnish Gibson used back then! The wood used here was maple, but it still took a good dozen coats to get the look I wanted.