Probably you enjoy the tool g+ offers to find related People to follow for your circles. The same algorithm you can use to find your Top related Twitter follower.

Just try follwoing

string site:twitter.com @Tweetname

First result will be your account followed by your public lists then it will show your most relevant Tweet friends. Without any score, ratting or influence. How often you tweet RT or how old the tweets are will not influence the result.

You will be surprised how precise it is even if you are loged off Google Plus