Mica: I've been using T-5's exclusively from seed propagation or cloning all the way to harvest for the last couple of years so here's my two cents worth. It all depends on the size of your wallet. I'm assuming that you have 5'000K or 6'000K lamps in your fixture now. It's pretty much a matter of choice. I have both and they both work fine from seed propagation or cloning through vegging.
You can flower under T-5's but you'll have to change the tubes to a range of 2,500K, 2,700K or 2,800K. A friend even uses 3,000K, but I don't. I have 2,700K and 2,800K lamps and I can't see any big difference.
A couple of friends veg under T-5's because they use a whole lot less electricity and burn much cooler than the other lighting options flower under HID and HPS. Admittedly, their buds are tighter and more photgenic/prettier than mine but they're no more potent. Since we all use different brands of nutes I don't think that's critical.
The only negative comment I would make from your post is that you're using a two tube T-5 which is very narrow and lights a very narrow area. If your plants are in 1 gallon pots and they're lined up in single file it might work but as you plants bush out you'll notice that T-5's don't do much beyond the immediate area directly under the fixture. The light doesn't spread effectively beyond the fixture size like HPS and HID. But then you can't hang HPS's or HID's a couple of inches over your plants like you can T-5's without frying them.
I have a 2' by 4' by 6 1/2' tent and I only grow my personal meds. One four tube fixture four feet long only lit up half my tent. Every plant not right under my fixture grew scraggly trying to stretch to the light. Now I have two four tube four footers hanging side by side and I can get equal vigorous growth in all eight square feet. It's something to consider. I hope this helps. HSA