T5 mod - Am i crazy?

[RobB'z Reef]

So I'm going thru the equipment gathering phase for a 180 (6x2x2), my first tank in 15 years. I've always been a DIY'er to a large extent so I tend not to shy away from building/modding for plumbing and electrical. I know i want a T5/LED hybrid approach, but i want to wait on the LED portion until down the road. I really do want to play with dimmable T5's over my 180 and I'll be employing a Neptune right off the bat so that part is covered. I don't think 48" bulbs will cut it length wise, but looking at the Aquatic Life 36" Hybrid, bolting two of those together would cover the tank well without hanging over. However they aren't dimmable like the DX18's and those are about $250 apiece more, they won't connect well and they'll hang over the edges of the tank too much. I was thinking it might be plausible to buy two 39w HEP replacement ballasts and swap them out saving me almost $300 and getting me the fit and functionality I'm going for. Maybe I'm over thinking it all, it has been a while. Anyone have any thoughts on this approach, anything I might be overlooking?

Thanks in advance