It will work to light a bare tube, although not at full brightness,
of course. Here are some pictures of a similar
inverter driving a nominal 27W CFL (not twisty, but otherwise
presumably the same), while drawing about 0.5A at 6V. (3W!)
It's brighter than I expected (brighter than the same
inverter driving a 4W normal "tube", for instance.) Not
nearly as "bright" as when driving a small CCFL, though
(I will not hazzard to guess about total lumens...)
http://www.geocities.com/westfw/electronics/fluor-1.jpg
http://www.geocities.com/westfw/electronics/fluor-2.jpg
As I understand it, a fluorescent ballast or inverter is
sort of like a LED driver, in that the ballast contains any
current limitting that is needed. So a 3W ballast will drop
3W into whatever tube you connect it to, and whether that
actually results in light is up to the tube. (also, whether
the tube will get damaged, etc.) CCFL inverters tend to be
a bit more finely tuned to the tune they're connected to, as
you can watch the current consumption change quite a bit
depending on what tube you connect, but I've gotten light
out of quite a variety of tubes to emit SOME light. (4W
straight tubes, xxW circular bulbs, and the CFL pictured,
not to mention a variety of the sorts of CCFLs they're supposed
to work with.)
The inverter's failure point seems to be the insulation of
the secondary transformer winding. Turn up in input voltage
too far, and you start to get arcing and burnt insulation.
The attempt at a micro-sized jacob's ladder was not successfull,
though I eventually did enough damage to the inverter that it
would no longer light up anything...
Enjoy
BillW