http://scorevoting.net/PropRep.html
Regarding single-winner methods, Score Voting is best. http://scorevoting.net/BayRegsFig.html
If you could directly measure internal sentiment and use a consistent function to map it it to scores, score/range voting would be a good method, and mathematical simulations tend to model this case rather than reality.
(Approval voting is good for group decisions with non-secret ballots where people can opt-out of the activity selected, and an "approve" vote is also a commitment to opt-in, because then there is a consistent meaning; range/score voting similarly can be good in group decision-making what shows are tied to a concrete price that is to be paid for or to avoid an outcome, which again makes the ballot marking have a consistent meaning.)
But it might be politically possible to get that prohibition on multimember districts narrowed to what it was designed to deal with, which was having multiple at-large plurality-elected seats to suppress minority representation. (When it was passed, no one was using multimember districts with PR, so they simple weren't a consideration.)