Honestly the best way to get an idea of what you want is to go to a store or a persons house an look at the difference in t5 and MH. Bulb choice with t5 also makes a dramatic difference, as well as good individual reflectors. There are crappy MH and T5's out there so be sure an do your homework
. Honestly for a small tank the viper would be okay, but for a 29 i would go 150 watt at least, the color from the 70 watts is not very nice. Pendants would work nicely for you tank, and they have a lot of flexibility. Some people, just cannot live without the shimmering effect of MH, while this is recreatable with LED'S, it is not the same visual. You might end up being part of the shimmer crowd.