I don't know how I'd handle someone giving me a look like I'm crazy because i handed them an offer on a napkin and assured them it's okay, 'my buddies on bp said it's cool, no lawyers needed, we can do this, idk exactly how but I'll Google it tonight'. but just don't quit. 

What is required is that there be a piece of paper - list provided by the QI, email to the Qi, contract (executed or not), cocktail napkin dated and signed, etc that identify the specific properties you are identifying as potentials.  

People sell celebrity used napkins on Ebay for lots of $$$ because someone wants to buy it.

By that I mean, just because the property next door has CR=7.5% doesn't imply that yours  will or should be the same.A back of the napkin equation for ARV would be the sum of all monthly rentstimes 12 months; this get's you to the GSI(Gross Scheduled Income)times a GRM(gross rent multiplier) and reasonable number is 10and the ARV is ~= FMV just calculated.

Even on the back of napkin underwriting think about this...4 decent size rent readies - 5k/each = 20k +Appliances, paint, & carpet on 60 units = $1,500-3k/each = 90-180kI would say you are at a minimum 200k without any other items.  

I can't recommend enough doing a little napkin market research using AirDNA or Everbooked.)

@Tyler Hull that deal passes my napkin test and something I would explore more.

I'd also make sure they're keeping the unit clean and sanitary.

Writing a contract on a Hardees napkin?

If the asset manager has been on the job for about a week, they might accept a figure scrawled onto a cocktail napkin.