It is a crawler. Perhaps 1 1/2” between bulbs. I pot mine in shallow plastic 5 or 6” azalea pots. They can remain in those for at least a year.
I use a seedling bark mix for the lower half of the pot and sphagnum moss for the top half. I put them in fresh moss every spring. They are very shallow rooted orchids so if you put them in a deeper pot, it is all useless space.
For me under lights, they put out new growths everywhere. Maybe for a five bulb mother plant, I get three of four new leads, three quarters of those flower.
I have the clone Red Chimney and two other clones. It is my favorite Bulbophyllum.
This is another one of mine. Bulbophyllum Rothschildianum ‘Red Chimney’. I did not look up images of Red chimney in the AOS database as it slipped my mind. I have heard of the clone for the last several years.