Hmm, not really sure about those particular bulbs, but "PC" by convention refers to T5 Compact Fluorescent bulbs although I suppose this is changing. I guess it depends on the type of ballast. If it's a magnetic ballast then it's likely a normal bulb and if it's an electronic ballast there is a higher chance it's a T5 or T6. What's the diameter of the tube? If it's a 5/8th inch diameter then it's T5. Someone else might have a better grip on these bulbs.
Either way 22 watts is a lot because the distance from the bulb to the plant is so short. This means a higher energy input to the leaf which accelerates CO2 demand. Whichever way you go, Excel or non-Co2, I would start off with a single bulb, no question.
Just about every plant, including stems is a low tech plant. In their natural habitat the lighting is often very diffused during the wet season due to murky waters and shading of the upper branches of trees or bushes. When plants are in a low light environment they adapt and become more efficient in that light. We disrupt that mechanism by throwing mega-wattage at them, so this is the beginning of the troubles - we then have to pump huge doses of CO2 into the water column in order to support the increased CO2 demand. If you keep the lighting reasonable you can choose almost any plant you want. They simply won't grow as quickly, that's all. Light is an accelerator. In low light the rate of growth is slow, in high light the rate of growth is fast - but only if the nutrient/CO2 demand is met. If you create a high nutrient/CO2 demand without actually providing sufficient levels then growth fails and algae attacks.
You need to decide your goals and objectives. Can you tolerate a dim tank and slow growth while not having to do a lot of maintenance, or would you prefer a bright tank with more dynamic growth with the penalty of more problems to solve? Choose the technology, most plants (with some exceptions) will adapt to either scenario.
Cheers,
Cheers,