dividing Bulbophyllum dentiferum

[Dima]

I have a Bulbophyllum dentiferum for two years now, and over time it has rambled far out of its flowerpot and onto the wire-mesh shelf it sits on. I would like to divide it. The questions are: (1) where do I cut the rhizome - close to the older bulb, midway between bulbs, or close to the newer bulb? The rhizomes are fairly long, between 2" and 4" each. (2) How many bulbs should there be in the new division? (3) When is the best time to divide? Right now it's growing two new bulbs (one on each rhizome coming out of the flowerpot), with the new bulbs not yet full-size but the new leaves approaching full size already. Should I wait or should I divide now? Thank you in advance!
P.S. to clarify: the rhizome length is 2-4" between two bulbs, not the total length, of course . There are 14 bulbs in total: 4 in the flowerpot and 5 on each of the two rhizomes coming out of the flowerpot.