Yes, I think the tank is sufficiently lit. Don't get me wrong, if I wasn't changing tanks around in the near future, I would probably look at a second unit, but for a 30" tank I think the light is good even at 24" deep, let alone 18". If you are indecisive on the unit, I'll be taking this apart in the coming weeks, and I can take a picture of the light over my 20 long sump, it has the same dimensions as your 29, only a little shallower.
So far I like the light, but it's my first LED to be honest. I had seen a few LED set-ups and none with a Vega, but some with a Sol and a few with a Radion or many. I kind of just got sick of trying to pick apart weaknesses between this and the Radion and others and just went and bought it. I'm not displeased at all!
And this tang?
I have absolutely no idea what it is to be honest.
When I bought it, the store didn't know and got me the shipping list and gave me it's scientific name. I looked it up and there seemed to be some confusion as to whether it was a mimic tang or a vampire tang. Neither of their names actually were the same, but the similarities are there, but not exact.
Anyways, I forgot what the name was, so anyone's guess is as good as mine at this point.