It's perhaps useful to note that IL used a similar method for over 100 years to elect its House until it was eliminated in 1980. The state was divided into 59 three-member districts. Voters could cast 3 votes for either 1, 2 or 3 candidates dividing their votes evenly (eg. if a voter only selected two candidates they each got 1 1/2 votes). Parties ran only two candidates in a district to avoid being knocked out by strategic voting, so districts had representation from both parties.
I remember those days, and meeting the local Pub in the House, who got elected with a handful of votes in the Hyde Park neighborhood of Chicago. It seemed like a bad idea, at least for essentially one party areas, but back in those days, the Dems liked having Reps in high income GOP areas in the collar counties, who often brought heft to their cause, and were perceived to help their party grow in those areas. The Dems no longer need that now, obviously, since they have largely run the table in that department.
