Fees should be clearly stated in writing, easy to understand, and justifiable.

Especially if you do 1 million on each house and have a 1 million umbrella for the business. 10-20 million is excessive and will most likely will get rejected by underwriting unless your rental income is in the millions or you can justify such an amount.

Do the repairs necessary to justify increasing rents. 

What is the value-add I'd really be providing to justify a fee?

Meaning you would have had to renovate the building to justify a swing in value within the last 12 months and that swing would have to be supported by higher rents.

We may operate this as a cost-plus contract, trying to lock down as many of the sub's prices upfront, but knowing any justifiable increases will be passed on to me.

Fees should be clearly stated, easy to understand, and justifiable.

Typically with a lot of investors the time doesnt justify the means when it comes to doing direct mail yourself.

They do this because they know the inspector needs to find something to fail them the first time (to justify their job).  

So don't let anyone tell you to not make an offer, if you've done your research and know your numbers and market and can justify them to someone else.