I don't prefer the 'trial by fire' method when it comes to investments. 

You shouldn't have too much trouble finding an SDIRA provider that doesn't charge for incoming funds no matter what the method of deposit is. 

My wife and I have been using the BP method of calculating operating costs for rentals in Houston but we were starting think that just using say 8% for maintenance, 8% for vacancy, etc is fine for a place that only commands $1000/mo in rent but really penalizes a place that commands $3000/mo in rent making it impossible to find a good deal.

If no, you have to find another method - Subject-to, private money, etc.

What method would be best for noise and most typical for fire code?  

What is your most successful method of finding the perfect deal?

. :-) It is legitimate, but like any funding method, has its pros and cons.

The feces stains and cockroach droppings are extensive inside the drywall and on the wooden studs and joists.What is the best method for cleaning off the surface mold?

This "house hacking" method is what got me started too.  

Eventually I'll like to move into MFR at which I'll be looking for other creative financing methods.