Questions about finding a contractor for BRRRR

[David Lee]

Long time BP member, first time post. I am looking to getting into investment properties in South Florida (Broward County) using the BRRRR method. I'm currently in the stage of building a team. So far, I have found a hard money lender, which feels like a win. Now, I'm looking for an investment friendly contractor. Was hoping someone could give me some advice whether it's specific to my region or in general. A few things that I'm not so clear on:

1) Should I be finding a contractor to work with long before i make my first offer on a property? And if so, any specific questions I should be asking them? Should I be transparent that I'm new to investing? 

2) Typically, how does the process work once I find a property? i.e. when do I have the contractor take a look at it and give me a bid or estimated rehab cost without wasting their time (before i offer or after its under contract)? Is it recommended to offer them incentive to look at the property (cash etc)? It's a little daunting never having estimated a rehab and trying to run the numbers when I'm not confident in my accuracy. Sure I can watch videos and read how to estimate the costs, but until I actually see a professional estimate I'm not going to be too confident in my analysis. Especially in the South Florida market.

I guess I'm just a little unclear on the process of how these things work. I want to make sure I have reasonable expectations of the contractor prior to giving them a rehab job. 

Thanks for the help!