[pikevi]

I am not knowledgeable in the area of light spectrum (nor orchids).

According to the graphs L36-77 (or L58-77?) seems like the right spectrum for plants. Your choice of L36W 76 seems like the best of the rest since the 1st one is not available.

(N.B:I am not sure if the numbers correspond to the graphs and it is a bit confusing.)

I think optimum for photosynthesis is around or just below 400nm and other activities such as hormonal regulation takes place right across the spectrum but moreso in the 500nm or more, I believe. I hope someone will correct me if I am wrong.

The last one (L18-67) is interesting and coud be useful for growth. I have used that range for my aquarium plants as one of a pair of fluorescent lights.
They are quite expensive here.

I am sorry I can't be any more specific.

I hope someone will add more to help you out.