K, <strike> 173</strike> 167
=

    o:"METHINKS IT IS LIKE A WEASEL"
    i:0;{~x~o}{-1($i),": ",(r:a@*&b=c)," -- score: ",$c:max@b:+/'o=/:a:{x{if[0~*1?20;x[y]:*1?s];x}/!#x}'100#,x;i+:1;r}/28?s:"c"$32,65+!26;

/

    0: FQRZPHACDIBHZOUUCYKKFBJWVNVI -- score: 1
    1: FQRZP ACDITHCOUUCYKKFBJWVNVI -- score: 2
    2: FQRZP AFDIT COUUCYKKFBJWVNVI -- score: 3
    ...
    51: METHINKS IT IS LIKECA WEASEL -- score: 27
    52: METHINKS IT IS LIKECA WEASEL -- score: 27
    53: METHINKS IT IS LIKE A WEASEL -- score: 28