Help with Dendrobium Spectabile

[mmorehead]

I just purchased this over-potted Den Spectabile x Alexandrae and posted a picture here. I am new to this species, and would appreciate any advice on how to care for them properly; lighting, temps, watering, hummidity.

One thing I am concerned about is the canes. All but two have begun to shrivel, and I'm not sure if it is a result of its current environment. Some of the leaves are turning yellow and crinkling, too, which also leaves me concerned. It has a new growth which has increased in size on one of the canes... so that makes me feel that I'm doing something correct.

I also need to know if I should repot it. If so, what size pot? And what do I look for with the roots?

I haven't been able to locate many sites containing care info. Please help! I greatly appreciate your input!