If I burn out for a bit can I go down to working two days a week, or do they expect a floor to be applied?

Absolutely, I didn't mean "tied directly" to mean linearly, but even that caveat being made I would happily weather through months or even years of like 1/2 or even 1/4 salary. If I worked at a company where say the highest paid person did not earn more than say 20X the lowest paid and all salaries were tied to the revenue I feel like on compensation structure alone I would be more likely to work there than most places. I think "the compensation scheme NOT creating a heinous caste system" is actually really high on my list of things I would want in a workplace.