Mini Den cultural info needed! Help!

[shakkai]

I needed to find more information on three species: agathodaemonis, cyanocentrum & vexillarius.

I know that agathodaemonis now seems to be considered the same as cuthbertsonii, so I will assume conditions should be the same - unless someone tells me otherwise!

They are listed here:
Equatorial Plant Company Flasks
as follows:

Dendrobium agathodaemonis - IOSPE PHOTOS
Oxyglossum
Miniature with red cuthbertsonii-like flowers. Cool.

Dendrobium cyanocentrum - IOSPE PHOTOS
Oxyglossum
Miniature, cobalt blue flowers. Intermediate/cool.

Dendrobium vexillarius - IOSPE PHOTOS
Oxyglossum
Small plant with bright orange flowers. Cool

What I'm really hoping are some max/min temps - rather than just a 'cool' guideline which varies quite a lot in interpretation. Is it cool like cuthbertsonii, or cool like jacobsonii (bordering on cold)?

I'd also really like to find out light and water recommendations/requirements.

I'm really struggling with the cyanocentrum. It seemed to be doing well, and putting out new growth in cool conditions, but then it started to go downhill and all of the new growth died back. I tried moving it to more intermediate conditions, but then established leaves started dropping. I am assuming that this isn't one of the dens that drops all of its leaves and goes through a rest period, so something it definitely wrong and I need to fix it before I lose the plant. The roots are still white/green (but are no longer growing) its the canes that are dying back.

These came potted in sphag, but I'm wondering if maybe they would do better mounted, as most of the photos appear to show them mounted.