I would agree that Dubias are prefered, as the Lobsters are fast, and do climb glass and plastic.
That being said, a Lobster being faster is a good thing when it comes to getting a dragons attention.
To figure out how many to start with, track how many of what length you feed per week. Let's say you go through 30 Lobsters that are about 3/4 inch, in a week. I would order 5 weeks of feeders (1/2-3/4 inch, 150) and then order 50 adults, 3 Female to each male, and another nymphs of various sizes. This should be close to the minimum you will need, if it is short, you can order some more later.
Dubias are also much more meat per roach, so you might want to look at them as your feeder, or both.
hope this helps.
Nick Barta