I installed Hustle on one of my sites which was working on the staged version of the site but when I tried accessing the setting in the production site I would get a blank screen, The only difference between staged and production are the number of posts/taxonomy counts ( a couple thousand on stage vs 50K+ on production) . I was running into a memory issue with hustle on production and tracked it down to lines 367-375 in hustle-module-admin.php which was trying to get all my custom posts where I have the majority of my posts. I commented these lines out and created an empty array and now I can access hustle's backend. From this, it appears hustle isn't supported for large websites. It doesn't appear removing these lines of code broke anything else so I don't know why it's there.