To give you something as a reference based on your budget (30-40% down with $1.8M), the general cap rates you will see in the Bay Area are roughly 3-5% https://www.loopnet.com/Listing/1047-Rich-Ave-Mountain-View-...https://www.loopnet.com/Listing/1180-Saranap-Ave-Walnut-Cree...You will find higher cap rates and more 20+ units buildings in SF, Oakland, and Richmond, but keep in mind of their stringent tenant laws. 

Those assumptions above may not even be entirely accurate, that's just what I've been told plus what I've deciphered from the zoning table. 

What are you bringing to the table?

The 4 guests smoked marijuana in the house (strong smell), broke a window blind and a picture, put a hole in the bathroom wall, chipped an end table and worst of all vomited on the couch and front porch.

By the time I got to the closing table, instead of me bringing a check, they gave me a check.Fast forward to today, it has more than doubled from appreciation and cash flows a ton, and I was able to get a great property manager in there to handle EVERYTHING.

Our bank will let us use equity that exceeds 25% across multiple properties that are either owned free and clear or where they hold the first so long as the deal still cash flows with however much cash is brought to the table.

These do tend to be more expensive but are also on the table as an option.

You generally would find that depending on what deals you have at the other end of the table best helps decide this answer.

He would need to find a place to live,which would take money off the table for collateral in his next deal.

If you don't mind my asking, how did you find the deal to begin with, and did you have some hint that owner financing might be on the table from the get-go?