So I am trying to find  a GC for upcoming potential BRRRs and not sure where to start.

I am house hacking right now and I just bought my partner out of the house and he moved out. With that being said I have a whole third floor that I want to renovate. Would it be a good idea to vet a new Gc by getting estimates on rehabbing the third floor with carpet and mainly renovating the bathroom? Is there a website I can have people bid on the work or what is the easiest ways you have found to find the best GCs?

You will get about a million different answers to this question. In my opinion the best way to find any type of professional is to get recommendations from family, friends, coworkers, etc... Once you contact them, check into their qualifications, and make sure your personalities work together, this will be important when working through tough projects. 

As a secondary way to find good contractors, speak to contractor sales reps from any local lumber yards. The more established contractors typically order their material directly through contractor sales reps, as opposed to making daily trips to Home Depot or Lowes. The contractors sales resps will know lots of contractors and can give you some good options of ones to interview. 

Hope this helps! Good Luck! Aaron

@Walter @Aaron Poling Local lumber yards! Great idea. I didnt even think about asking these guys about reccommendations. Thanks for your response. That was very helpful