I can't speak from personal experience, but I know Eurotubes.com has a set of JJ tubes that will help your Stiletto be "smoother." They describe it as like an Eric Johnson/Santana sort of sound. They explain how it's done, too. I love websites that actually help! Great vid, btw!
I have the premium set off JJ from Eurotubes in my stilleto. I think they are an improvement from the stock tubes that came with the amp, but there is no Eric Johnson tones in there because of there gold pin tubes. Nice marketing though.
Well the op is definetley playing the right song for Dumble tones. A good example of Dumble clean tones would be SRV'S Lenny, and Riviera Paradise. Especially live, Although he used several amps at once (Dumble, Marshall, Fender) When he wanted that crystal clear bell like clean, it was through the Dumble alone. His studio version of little wing was supposedly a Dumble loaded with KT66 tubes. This is my particular favorite tone.