Do you have a thermometer? Put a thermometer in the tank and see what the temps get up to after the lamp is on the tank for almost a full day. If it gets above 90*F for an extended period I would back the light up (raise it). However, if your plant is doing OK as it is there is no real reason to change a currently well working setup, at least not this growing season, make the switch after dormacy when it comes back to life.
Don't worry too much about spectrum, the daylight spectrum is really of "minor" importance, plants will use light in whatever spectrum they can get it, the most important thing to a plant is quanity of light, quality is second. Most softwhite bulbs have fewer lumens than daylight spectrum which is why I shun them.
I believe a balanced spectrum light is nice because of several reasons: too much blue/green oriented light can cause etoliation or make the plants "leggy/stalky" (just as if the lights are too far away) and too much yellow/red light will cause "stocky" short and wide growth with too short of internodes between leaves possibly OK when growing in terrariums but using abulb of ballanced spectrum seems to give plants better colors if they are types which produce patterns and colors (like Nepenthes, Cephalotus, etc).
I would go with that 30 watt Sun A Lux personally as it will be just as appropriate if/when you decide to upgrade to 5 gallon tank.
Might I ask where you found them for sale? That sounds like a great spectrum! Are they biax, double biax or simple screw in compact flourescents that go into incandescent fixtures? I'd like to try one myself over a small tank as an experiment if they are commonly available in the US.