Any solid core team will need heals and debuffs. 2 heal skills seems to work well. Stacking debuffs such as atk/def down, atk down, and def down is also important. So form a team that can do both of those, using your hero to fill in the gaps as necessary, and you should be able to handle the majority of content without quadruple SSRs. Since Rs level cap at 50, you don't want to rely on them if you don't have to, but they can fill out a full team of a given element if need be.