Cattleya questions...

[The Orchid Boy]

I bought a Potinara Memoria Irene Feil 'Ruby Red' at an orchid show last weekend. It has the most beautiful blooms!
My questions are:
-When should I repot it? There is moss growing and a few small weeds are growing in the pot. The medium looks pretty good though.
-If I do repot it do I have to divide it? It has 10 growths and one back bulb.
-If I did divide it, would both the divisions bloom next year or would they be in shock?
-I heard something about a "rest" for any cattleyas that don't bloom in summer? Is this true.
-Only one more question... I grow under T-5 lights and I had another younger cattleya under the lights a few inches away and the plant almost turned totally purple! This is suntan but I have never seen an orchid get so purple. How close should they be to the lights.

Thanks so much!