@flipturn That speaker is easy to drive so you have a wide range of amps to choose from. Its not efficient enough (unless you have a small room) for SETs (which should not be run past about 20% of full power in order to avoid excess distortion) unless you have a really powerful one. The problem with those is they audibly lack bandwidth.
If you are set on tubes look for a triode amp that is push-pull. That will get you the power you need; triodes have linearity that pentodes and tetrodes don't. They allow the designer to build a smoother and more detailed sounding amp due to lower distortion.