I just didn't want to be wasting their or my time.

I was fortunate enough to have a great team of contractors that I work with, They provided me with solid numbers upfront and stuck to them.

Does anyone have a solid number that they use as an estimate in their calculations for metered units? 

I think you'd be wasting your time.

I don't want to waste the owner's time, nor my time with a tire kicker.Next go to the property with the buyer, instruct the buyer to ask you any questions they may have, but NOT THE OWNER.Let's suppose you do all of that & the buyer goes the next day to talk with the owner to try go around you.

If you are a newbie, often brokers feel you out by sending you all the bad deals that their solid buyers didn't want. 

Agents don't normally work with one person at a time so bugging an agent for every little property that is missing information seems like a huge waste of time.

The attorney i wrongly checked with never heard of a lease option so that was a waste of everyones time and money. 

And the management is only one piece of the work anyway, there will be more.Anyway as far as "how is this possible" as you say, the only way it is possible is if you have a documented track record of solid results with years of experience and a business infrastructure.

For example, you can probably get a few properties with conventional financing, but by the time your looking to scale, you've hopefully built a solid reputation for yourself as an investor.This reputation will allow you to tap into things like hard money lenders (if you can do some cash out refinances on earlier properties to pay off the higher rates hard lenders expect).