However, my outlook and risk tolerance has certainly changed!

All boils down to risk tolerance and what you're doing with the project. 

I would have to know your risk tolerance, your desired cash on cash returns, your location requirements to see if what you are trying to do is realistic or not.

With the larger buildings, the more leveraged you're likely to be, so it comes down to your risk tolerance.

We handle this way:  leases have a strict zero tolerance clause for drug and domestic violence issues. 

Right now I have a high risk-tolerance and little to no commitments.

Risk-preference is all relative but this would be outside of my personal tolerance and I'm actually doing deals in a few rougher areas on the South side of Chicago.  

It can be based on the ARV like you're thinking, actual LTV (as-is), or some other algorithm(s) specific to a lender's risk tolerance, experience, knowledge, etc.

Depends on your goals, your timeline, the amount of money you are planning on investing, the cash flow it generates, if you are married or single, your annual income, your tolerance for "tenants, turmoil & toilets", and a couple of other things.

If you are a ultra conservative very low risk tolerant investor you could pay down a income property mortgage but that is obviously going to reduce your return on your investment to a ceiling of the prevailing mortgage rates.