How do I scale PR and MPR with my score? (in General)

I haven't played in a lifetime, so I forget how to make it so that my score, pr, and mpr remain somewhat even with one another.

Actually you don't want them the same. PR is sort of your base power, MPR is modified by your equipment and should be higher, and score is the result of battles and should be even higher. Successful battles will raise your score and unsuccessful ones will lower your score. The bigger the victory or loss the bigger the score change.

Slight correction. MPR is minion PR. It is the base value not PR. So swap those two in the description above.

as an additional tip, try to find people with high scores that you can beat. the higher the better because of the extra % bonus you get. sometimes you may have a strategy that trumps other teams with higher mpr/pr/score which is valuable for farming