Of the four times I saw the Splinter Group, they never played "Oh Well". And, the times they played "Rattlesnake Shake", they barely reached the 5 minute mark, much less 20+.
The longest song I ever heard them play was "Black Magic Woman"...the last time I saw them (at the House Of Blues in Downtown Disney in May 2002), it fell just short of being 15 minutes long.