Can Audio Physics be run on low power tubes?

Saw a seller of Padua's said that he used SET's to fire his Padua's to good effect.But I find many folks told me that I could run a pair of speakers with SET and it was a wash out.The ad seemed to imply that the non-Ring Radiator tweeter was easier to drive than RR model.Still can't figure out why AP who keep speakers in thier line up once introduced (instead of some companies that have a new-gewhiz-banglatest and greatest every two years) but dumped the Padua pretty quick out of their line.

Considered opinion I have collected is the Spark and Virgo were best models.Tempo's I am told need to be run loud to open up.I had a pair of Spark III's for a few weeks geting them for a freind and thought they were great especially with ability to give good dynamics even at low volume levels something again I am told the Tempo will not do as well.For me it would be tough to even think about the Scorpio given what a used pair of Virgo's cost but I guess for many (including me) space has to be a consideration.But I digress.Tubes and AP's anyone?
Thanks
Chgazzbo