IMO to merit a tribute act, a band/artiste should have had enough 'hits' to fill a 90-minute set.
Let me now qualify that: To play only to fans of that band, you just need to learn the band's 'best' material; but to fill venues with average gig-going punters, the band needs to have had a lot of mainstream hits.
Hence, good choices for tribute bands: Queen, Rolling Stones, Abba... Not so good choices: Culture Club, T'Pau, Dr Feelgood...
If 3-hit wonders have to join forces with others to fill the bill at a Butlins weekender, what hope for the tribute bands? And when I saw Wilko Johnson, he was on a triple-header with John Otway and the Hamsters.
My advice: Yes do the Feelgoods stuff, but add in other material from the same genre/decade/trend or whatever. Ian Dury and the Blockheads? The Pirates? Dave Edmunds etc?
[b]EDIT[/b]: In short, what crez5150 said ∧∧∧