Input on Growbright fixture please

[margitks]

Hello everybody,
I am back to pick your brains again

My wonderful boyfriend is getting a new light fixture for me for Christmas
and I have several questions regarding its capability and installation.

This is a link to the fixture:
HTG Supply - GrowBright 4 Foot 4 Lamp High Output T5 With Choice of Bulbs

A fixture for 4 - 4foot high output T8 lights.
Out of the two bulb choices, I think I would need to use 4 6500K Grow ones. The second choice offered are 3000K bulbs.

My questions are:

Are the 4 6500K bulbs the correct choice or should I choose a combination of the 6500K and 3000K bulbs?

How high above the growing area does this fixture need to be installed?

Am I correct that this light is bright/strong enough for blooming Cattleyas? I would love to add them to my small collection of Orchids.

Your input is greatly appreciated,

Margit