Even though Twitter's statuses/retweets API endpoint is limited to the last 100 retweets it is possible to use the search/tweets endpoint to search for the retweets using the text of the tweet. Caveat: This is only possible for tweets that have happened in the last 7 days, which is furthest back Twitter allow you to search for tweets in.
For example here is how you can get the retweets for this tweet and analyze the users in a spreadsheet.