I agree with Thomas about the lengh of the tank, but 150 gallon (around 600 liters, right?) could be enough, to me.
I have been keeping Cyathos for about 20 years now and IMO, with no doubt, the best choice are a group of 8-12 medium size (3-4 inch) tank-bred individuals for this species.
Wild caught Cyathopharynx very often arrive in quite bad condition and, even this is not the case, they take a very long time to settle in our tanks and to show their wonderful colours again.
In any case full grown males have often a short life in particular if they start again to have a sexsual activity.
Tank-bred ones start breeding very early and show their colours when they are only 4 inch (if there are not bigger specimens in the same tank) and they live much longer.
In the pic you can see a tank bred Sibwesa foae 4 (!) years old.
About the variant check in a good book a choose by your self, my favourite ones are the so called "green-copper" foae (Kabogo-Halembe-Karilani-Sibwesa), but all, furcifer included, are wonderful!
Last advice, Kilesa and ochrogenis Xenos are bottom oriented fish too, not good tank-mates for Cyathos.
Cyathos are better by themselves but you could try with a group of Cyprichromis leptosoma
and a few little shell-dweller lamprologus.
Hope this helps you (and sorry for my English),