Make sure to check reviews and go with a reputable one!

Hopefully someone from the area can chime in but shopping quotes from reputable and well rated or referred PMs will illustrate a better picture for you.

If you haven't already - find a reputable lender to qualify you and give you idea of what your PITI would be at 600K or other price point. 

So here is my question, I know a reputable firm that provides this service but how can I set up the 'business partnership' where they are my chosen vendor for this service without my clients trying to go behind my back to deal with them directly, thereby kicking me out the middle.

However there are some reputable new construction builders in the area.There is, as you likely know, a housing shortage and, once Caesars Casino opens at the end of 2024, they anticipate 2 million visitors a year. 

The costs of a QI are also often relatively minimal in comparison to the interest and penalties you would pay if it is blown up.You are also parking significant sums of money with the QI - that alone is worth using a reputable QI to ensure your funds don't disappear. 

Having lenders or partners upfront places you in a better and more confident negotiating position and in the event you find a deal and can't find the money, now you lost the deal and have to back out damaging your reputation as a closer.

If a deal crumbles and you lose money it won't be because of the financing, given you're dealing with a reputable broker or lender who has closed 100s of deals. 

However, I have a trustworthy and reputable private lender that is willing to fund my first few deals.

It would also be wise to have a reputable roofing contractor who has been in business for several years walk the roof and give you an estimate.