In my opinion whittakeri is one of the easiest tuberous dews to cultivate, particularly in its dormant stage. You can keep it bone dry or slightly moist during summer. I think it actually PREFERS slightly damp dormant conditions in that the tubers I have in that arrangement are nice and plump while the ones kept bone dry are slightly shriveled up by mid to late summer. It also is an early riser, producing above ground growth early in autumn.
The other cultural conditions in the growing season are the same as other tuberous species - cool temps (40-65f), as much intense light as you can give them, and a standard cp mix of 50/50 peat sand. I have found that they grow well in straight peat to straight sand and in everything in between. Use 1/2 gallon or larger pots.