I did add the spiral daylight bulbs and the light is brighter than the single 15 watt.
As a test for later CO2, a got some of those plant tablets that fizz (8 weeks worth for $5 MegaFS) and 24 hrs after the addition, the tank is at 7.4 pH., down from 7.8 of aged dechlorinated water. I'll monitor it daily to see how wide the pH swing is, but I think it will be moderate as you say. The same stuff is $2 online and so for $0.25 a week I might be able to just keep this single tank going on fizz tablets.
I'll run it a week with no filtration or water movement to watch pH, then test another week with that smalll filter going before I choose fish. I'm thinking here that the filter will drive off a lot of CO2 and I'd like to let the plants get a foothold.