For horticultural use, you really don't need to build a rig in most applications. Plants are different than humans in one respect, in that if you expose one area, the entire plant will react as if you exposed the entire plant. If this were true in humans, you wouldn't have farmer's tans, as you entire body would tan from the exposure. Keep in mind, you still need to expose as much of the plant as is reasonably possible, but you can typically do this with off the shelf fixtures.
Another thing to remember is that lamps such as the FR32T8 Universal UV
are pretty strong in the UVB range, and your lights run all day. You can use either F32 (32 watts) or F40 (40 watts) fixtures designed for single bulbs, and just run them on your standard timers. For most plants, you will be running 4 to 6 feet away. The best judge is your eye, look at the plants (after turning off the UV light, of course) each day and make sure you aren't damaging them overly so. A small amount of damage is expected, and you need to either adjust the distance or the times the lamp is one to achieve this. It is as much art as science, and every plant is different. Remember, the goal is to cause a tiny amount of damage, so the plant reactions by producing its own sunscreen (ie: flavonoids or other resins). Don't forget, these lamps have their own built in reflectors, so be sure to AIM THEM. They should be pointed directly at the plant, usually at one side or the other, or top down.
We are currently beta testing a new F54T5 lamp as well, with the final name to be determined later. These are very skinny lamps, just over half an inch in diameter, but use 54 watts of power, making them a VHO style bulb (Very High Output). These are unlike our T8 and T12 lamps in many respects. First, they do not have a reflector built in (at least this batch of test bulbs) as it is very difficult to do on a lamp this small. Second, they have visible light phosphors in them. This is to dampen down the UVB and prevent damaging the plant. These are designed to be used primarily for plants, and to be run 12 hours per day. This is why we have about 5% UVB, around 30% UVA and 65% visible light phosphors in them. They are to be run only in F54 fixtures, and should have a polished aluminium reflector provided (most of these fixtures come with this as standard). In a standard 6 lamp rig (providing all the light that the plant gets), you would use one of these lamps. Again, you aren't really building a rig, but if you want to use these differently, you can buy an F54 single bulb fixture for around $40 on Amazon.com.