Light question
 

I have a Ruby Slippers (Phrag. caudatum x Phrag. besseae) . The issue is while caudatum likes high light, besseae likes low light. So for this child how much light does it prefer?

This is a case in which I start with something in the middle, and be carefully observant, adjusting over time.

If you have other phrags that are doing well, start by growing them together.

In such hybrid conditions situations, some of the offspring will prefer it brighter, while others will prefer it shadier - and others can be anywhere in between.

Actually, Phrag besseae is very adaptable... I saw them growing in Ecuador on exposed cliff faces - lots of sun. I have found the species to do better in bright shade to occasional filtered sun.

Should I look for a certain shade of green in leaves?

My theory is that if the leaves are too dark, it is not getting enough light, too "chartreuse" or yellow, is too much light unless there is another cause. In the case of some high light plants that have the proper photocells, you can get red/purple leaves or spots as well (tells you they are happy). If you get no spikes/flowers or new growths (leaves/hands), then you are not giving it enough light also. They can live in sub-optimal conditions for quite a while but they will not give you flowers which are a notification of breeding ability.