With my experience of keeping and propergating plants for over 5 years. For a nice display tank with some nice plants such as Red Tiger Lotus etc, I would recommend atleast 2.5wpg. 3wpg and most plants will love it. Just make sure to have a few SAE (simease algae eatters) in the tank to keep the plants algae free. With the high lighting its recommended to have some co2 injection to equal the rates of photosynthesis. Having warm water, co2 and high lighting will ensure healthier plants and will promote them into budding (have baby plants). Ofcoarse the recommended lighting tempreture should be 6,500K. This is where plants photosynthesis, thats why most plant light are at 6,500K. Nowadays people use Power Compacts but I know some people preferr the T8 and the T6 tubes. I have used the VHO in the past without any problems. Now im using PCs.
All the best!
Mango