A common rule of thumb is to budget around 1-2% of the property's value annually for maintenance.Management Fees: If you plan to hire a property manager or use a property management service, factor in their fees as part of your operating costs.Contingency Fund: Always include a contingency fund in your budget to account for unexpected expenses or fluctuations in operating costs.Financial Modeling Tools: Consider using financial modeling tools or spreadsheets designed for real estate investment analysis.

But as a business model not such a great venture.

This will depend on the lender and their model (whether they're selling or holding this loan). 

@Ruth Bayang  slight difference is they will also put up 80% of the money for you as long as you roll into a HML with them.. they make a TON on these deals.. they make the bid fee.. they make a hard money loan then they list back.I was close to starting the same model in pdx but the 08 GFC derailed me.. its a brilliant model they have an UBER profitable...

And guess what, it's the agent model.

I think that he has a very good model. 

Real Estate is definitely not just a "numbers analysis" and you are definitely thinking about things the right way - but I think a good next step for you would be to spend some time putting a lot of this stuff into a (very) basic financial model/spreadsheets mapping out all the potential costs and estimates on effect (effect on value, on exit, different scenarios) - I think getting started with that framework should help with these decisions immensely

Part of my business model has been not just profit but an enjoyment for the work.

In San Antonio, I hired reps for this type of thing and the model they told me their previous wholesale company paid was as follows:Acquisition rep responsible for finding their own deal, contracting it for the company, getting it to closing gets 30% of the fee generated by the wholesale.

They seem to have a good business model and one of the owners is an investor himself which is definitely a plus, but they charge a leasing fee (to find and get a qualified tenant into the property) equal to 1 month of rent, which comes out to an additional 4%-8% on top of the monthly 10% maintenance/management fee depending on how long the tenant stays.