We can control it remotely and there's a physical key option for back up. 

Given that your 4plex MF property falls under this range, it aligns with the current zoning.However, to determine if you can build up to 9 units on the property, there are a few things to consider:Existing Structure & Occupancy: If you already have a 4plex on the property, then you'll need to see if there's sufficient land and infrastructure to accommodate an additional 5 units without violating other zoning requirements, such as setbacks, parking, and green space.Infrastructure and Utilities: Even if you can physically fit 9 units, you'll need to ensure that utilities (like water, sewage, and electricity) can handle the increased capacity.Other Restrictions: There might be other local regulations, covenants, or restrictions that could limit the number of units or the type of construction you can do.Parking & Accessibility: Increasing the number of units might also come with the requirement for additional parking or other accessibility features.Approval & Permits: Just because a property is zoned for a certain number of units doesn't mean you can automatically build up to that number.

If you have multiple SFR properties do you just have a single reserve fund and each month add a certain percentage of rents from all properties into it or do you try to keep separate virtual or physical accounts for each property?  

Don't get emotional on the physical presence, but do manage your expectations from the numbers.

One isn't better than the other, there are pros and cons to both.I like real estate because it's a physical asset and I like the market because of its' liquidity!

For the average landlord, make sure there is adequate cash flow to weather the storms -financial and physical.

I'm very hands on and would rather be able to physically see the property and keep an eye on things without relying on other people or taking time and money to fly out of state. 

California's own nexus rules regarding physical presence could easily be used against them in this case.

Market value is meaningless when the bulk of the return will come from cash flow and when the resale of the asset will be to another investor who will be holding for cash flow.I have a feeling Ben will agree with both of these statements above (correct me if I'm wrong, Ben)...So, Bob, if you're going to argue that cap rate isn't a good measure of return for one particular type of cash flowing asset (in this case, single family rentals), you're going to have to justify it better than just cutting and pasting someone else's ideas.Please tell us why you (not others) think cap rate is suitable for analyzing/comparing the return of all other cash flowing assets, but automatically breaks down for single family cash flowing assets (or if you think it breaks down for other types of cash flowing assets, please tell what other ones it's not appropriate for).To say that a mathematical model breaks down based on the physical configuration of the underlying asset (one unit versus many units) doesn't ring true for me.

Physically check in with them.