T5's should work great for your application. If you were to opt for a workhorse 7 you can run as many as 8 24" t5's off of it. Short term pc's may be easier to get ahold of, and since they frequently come up used you may find a great deal on them, but if you want the flexibility of more coral options (it is very easy to add in t5 bulbs for more light) or you want more color options, or you like the ability to change the bulbs every 12 to 18 months, t5's might be a better long term investment.
I have been running t5's for 3 years now (I also have or have had pc, halide, and vho) on aro, workhorse, and Icecap ballasts, and the claim by Icecap that they extend the life of the bulbs really isn't a big issue for t5's as the lifespan is so long anyway. The most important bulbs to replace are going to be your actinics as they will shift first, and Icecap really hasn't been able to make an impact on
actinic bulb lifespan. You are going to want to replace these annually reguardless of what ballast you go with.
Depending on what bulbs you choose and how many you run, it could also take you 4 to 5 years to recoup the cost of the ballast in bulb savings versus what you would have spent on another ballast and more frequent bulb changes. Icecap is great, dont get me wrong, I run their stuff, but at this point, unless you want to run this exact configuration for 5 years, that is a selling feature that shouldn't be the sole reason to choose them.
Also keep in mind that older icecap ballasts can cause issues with X10 modules and powerstrips, so if you/she ever plan on automating, you are going to need to plan to use line conditioners and specific circuits to allow the controllers to operate properly.
Reefgeek is also a great source for t5 lighting. if you are shopping around, don't forget to give them a call.
If it were my tank I would get the thing set to run 4 t5 bulbs, and then start with 2 and add the next 2 in until I reached the color scpectrum and light intensity I desired. A friend who owns an online coral business has sucessfully kept everything from maximas to oregon torts under 8 t5's (he had 3 such prop tanks) with impressive enough growth rates that he was able to make a good deal of money on them. The only thing that was fussy was
crocea clams, but they grew and flourished if kept high in the tank.
hth
