[petters]

Do I have to register for the SAT solver?

Their web page says: "We are currently in Alpha Test. Users can submit problems via our SaaS portal in Conjunctive Normal Form (CNF), which ultimately represents the normal form of Boolean propositions for the problem’s variables and constraints"

I have no problem providing real, hard SAT instances in CNF. It should be really easy to verify whether they have something good, unless they have a size restriction.