That is how I use the rule 

It is really hard to make the case that if you have a full time job, you would fall under the 500 hour rule.

I'm in Columbus Ohio and we ahve to build the same floorplan over and over and it's a group heard mentality. we build a three story walk up triplex designed for our infill lots

On a positive note we did build a new house to the specifications of a specific tenant. 

@Seidy Lasker Wash sale rules apply to stock options if they are deemed "substantially identical" to a security sold at a loss within 30 days, such as options with similar expiration dates or strike prices.

The 50% rule - in my opinion- is used solely as a quick back of napkin calculation to determine if it is worthwhile to do more investigating of a property. 

We manage a bunch of ADU’s and higher density new builds for investors in Raleigh and Durham.

To discuss other side of this thought process on new builds..

Or maybe a favorite way to stay updated on local rules?

You have to find a zip code that has a prevalence of multifamily and a pathway to build multifamily.