Should it be a percentage of net profits, a fixed fee, or another structure?

I know many people have done it this way,  but two major parts I am concerned about are 1) how do you handle all the paperwork such as W2's, 1099's business records, etc. without meeting in person?

After some research online, I am reading that the cost per square foot on a gut renovation of this nature in Stamford CT is anywhere from $150-$350, which is ultimately not very helpful, because at $150 per sq ft, this is a very appealing project with a total profit of ~$175K (46% ROI) and at $350 per sq ft, it very much isn't, because it would be a net loss of 83K (haha).QUESTIONS:What can I do refine my estimate a bit given that I am not allowed to a formal inspection on the property? 

The area is very desirable, great schools, restaurants, shops and major airports close by. 12 mins from downtown St.

If you intended to flip but now want to hold, that's one of the major reasons DSCR loans exist.

Spoiler alert- Phx is quite a saturated STR area, and many STR's (although some are doing great) are having major occupancy issues. 

You can often uncover major things with a little research before you view the property - Ages of appliances, HVAC system, foundation/cracks, plumbing leaks, small electrical things (bring an outlet tester), signs of previous leaks, termite damage etc.

Here are some things that have been most impactful for me:*Reinvested ALL profits from Day 1 until it was time to walk away from W2.

The majority of homes are owned by homeowners not investors so they fail to put themselves in the shoes of a homeowner or look at data from the standpoint of being in the minority. 

And hands down the #1 violators of tenants rights (I mean legit cringe stuff) are those large communities, not investors like those who make up the majority of BP.