Hmmm ...where to start? Ok, let's try this....
They might be "exclusive" but they are lacking in knowledge of current planted tank methodology (and technology) evidenced by the fact that they told you the T5HO
bulbs would be "unuseful" in 6-8 months (that was the case with VHO bulbs) Your bulbs will continue to be very useful for a year (or more, depending on duration of daily use , bulb temps, ect..)
The fact that they set up & maintain customer tanks is not in and of itself proof that they are any better than your average petsmart employee
The good news is, you've found one of the best resources available on planted tank knowledge, methodology & practice... The bad news is, it might well take you half of a lifetime to wade through all of it
Take a look around the journals here, look at the results obtained by the tanks owner, read about the methods they used to achieve those results (and learn from their mistakes) Ask questions (you've already started doing that ...kudos), decide for yourself whether or not those methods might work for you ...then & most importantly ...*get your hands wet*
After all, it's a hobby ... enjoy it !
As to replacement bulbs for your fixture, I would replace the actinic (blue)
bulbs with one of these two:
Remember, whatever you decide to do, please share some pics of the results with us.