AND the side you live on you can rent out a room or two depending on the number of rooms in your duplex or you have the option to maintain your privacy and sanity and keep it to yourself.  

The question is mostly a personal financial planning question and it depends on your preference and what balance of risk and access you'd like and would be comfortable with.

GC's get paid off of the work, not a flat rate... but in your experience, would you say that window of rate is generally 10%-20% project depending, or more towards 15%-30%?

@Matt PowersFrom my experience, deciding between short-term rentals (STRs) and long-term rentals (LTRs) depends on the market.

Deduct NEW property taxes after you buyDeduct home insurance costsDeduct maintenance percentage, typically 10%Deduct vacancy+tenant nonperformance percentage(we recommend 5% for Class A, 10% Class B, 20% Class C, good luck with Class D)Deduct whatever dollar/percentage of cashflow you wantNow, what you have left over is the amount for debt service.Enter it into a mortgage calculator, with current interest rate for an investment property, to determine your maximum mortgage amount.Divide the mortgage amount by either 75% or 80%, depending on the required down payment percentage - this is your tentative price to offer.If the property needs repairs, you'll want to deduct 110%-120% of the estimated repairs from this amount.Be sure to also research the ARV and make sure it's 10-20% higher than your tentative purchase price.As long as the ARV checks out, this is the purchase price to offer.It is probably significantly below the asking price.

Just depends on the situation/scenario.

If your tenant has a credit score worth maintaining they will not want an uncollected judgment to be on it.  

It all depends on what your requirement for cash flow is.

Starting with your wife and possibly your kids depending on age (for example, they can help clean between tenants, this starts  their education [Check with your accountant because you may be able to pay your kids and take a deduction].- - While you will do the lion share, can you take advantage of your wife's talents and availability?

It may even be higher than 5% depending on the area.