I run a MH HQI lamp with metal halides. I do grow palnts with T5
Daylight bulbs. T5 6500 are much whiter than 6500 MH bulbs in my
opinion.

Kelvin temperature is very subjective and will only effect viewing
experience. Some will argue red/yellow bulbs can enable alage but this
has not been my experience. I prefer 10K bulbs on my reef tank, but
have found brand names within the 10K range to be very different.
Ushio has a yellower apppearance than aqualine 10 K bulbs.

I would definately go with a 10K bulb with your set up, but the reasons
will be for personal choice only.