One thing, until you start getting bids, you are just blowing smoke.
Call at least four, probably eight, contractors with your build idea.
Get prices. Get them to make suggestions.
This will cost you nothing, and may amaze the heck out of you.
Also, write down the name of each contractor on a sheet of paper, or on in a document on your computer.
After each visit, note some salient facts;
Did he show on time?
Did he have an attitude?
Was he going to do the job by subcontracting or did he actually have a crew?
Write down his estimates for how long it was going to take.
Look him and his truck over. Look like he's successful, or just squeaking by.
How long did it take for him to get back with the paperwork? All of them will give you a written copy of the estimate. Look that over, good or bad? Did it take him two weeks to get it back? Or did he just guesstimate in the front seat of his truck and hand you notes?
I did all this, and man am I happy I did.
Price variance was 20-34 on the same thing.
That's before I upgraded my order after I had signed papers. Wanted more square feet, more concrete, but that was all added on at a good price.
The contractors I 'down-checked' were because;
1 was going to do the whole job himself, with very minor sub-contracting. That's OK, but his estimate was 4 months. His two references said his work was "Um, OK, but slow".
2 didn't show even the day they promised. Since punctuality on construction is everything...
2 Never showed at all.
1 was a very successful sub contractor, who used low bids on every single aspect. No people he used on every job. His references were all over the map. "Had to wait for weeks for concrete, or roof, or whatever".
The one I picked had the lowest bid, but what sold me was 1. He wanted the job. 2. he seemed very competent, handled all my questions and pointed out things that would help. 3. His references (many) all thought he did great work. 4. While he never picked up a hammer, or even came to the job (except on friendly 'visits') he used mostly the same people over and over. When he did subcontract (garage door) he sent two local, good firms out. I met and talked with each of the door installers, and when I called my contractor and told me I like one of them over the other, he didn't argue, or anything, just said 'then that's who we will use'. I found out later it cost him more to go with the guy I liked.
Net result, I would highly recommend the contractor that did my job.
Told him he could use me as a reference, but he has so many that I never have been called.
I have hired several of his employees for 'moonlight' jobs, with the contractors consent, since then.