Clearly these are just example numbers, but it is how I would look at it.And then layer in if refinishing all the 1 beds is a $100k renovation, but converting into a 4 units is a $150k renovation, now you are spending more money to create less revenue AND have a property worth less at the end of the day.  

Much will depend on the price of the property, for sub $100k I’d expect to pay something extra. 

But some advice already said.1) Learn how to reduce your expenses2) Pay every month like you would be a tenant 3) Find other ways to make additional money - does it have a guarge, maybe rent that out for extra cash flow? 

Make sure to have thorough inspections done and factor in extra reserves just in case.

My goal is to keep things clear and flexible: I’m considering a setup where I offer my services for 2.5%, but if the seller offers 3% or higher, I keep that extra difference.

You could then get more sophisticated and factor in refinances after 5-10 years and how that money could be re-invested into acquiring extra units. 

A few patches might give it those extra miles without throwing money at a major repair too early.Think of it as using each part to its full potential before moving on to something new.

If you trust your contractor and can stay on top of the project, you might not need a property manager my understanding is the property manager is playing the contractor's role for some smaller projects, not another layer on top of the contractor. 

So it would be the same in some cases, but at least you would have extra funds available.

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.