My species won't grow

[Paphluvr]

From your description of your growing conditions I assume that you are growing them in your living area and that the winter temperature day and night is maintained in the low seventies due to your heating system. This is the time of year when I would normally try to give them the larger temperature differential (58-60° nights, low 70's days). Some species or hybrids aren't as fussy. As to light length, I haven't grown under lights in some time but when I did I kept them on approx. 16hr. in the summer and 14hr. in the winter.
How do others feel about this?

[phraggy]

Paphs are very slow to adapt to new conditions and can take upto a year to do so. Regarding watering I would let them become dry before rewatering. Dryness for a short time will not kill them but keeping them too damp all the time will destroy the roots by denying them access to air. Keep them on the low light side and try to raise the humidity.
Good luck,

Ed