County area of Murrieta. I’m hoping that the 50% rule doesn’t apply. There’s several large steel buildings in the area. Some of my neighbors have horse barns as big as their homes.
I live in the City of Murrieta and my garage is a 40'x50' and my home is 2800 sqft. My garage doesn't meet the current Development Code 50% rule. Luckily, my garage was built in 2003 when this requirement was not in effect and is grandfathered in. I bet your neighbors with big structures are in the same boat as me; they're grandfathered in.
With any luck, hopefully the fact that you have 5 acres and out in the county will change the requirements for you. I'm only on 1 acre and in tract home style neighborhood. A horse barn is treated differently than a garage, because a horse barn wouldn't be storing cars. Cars are considered "dangerous" because of the potential of storing lots of them (hazard of gasoline) and working on them ( ie welding etc).
The new Fire Marshall is really knowledgeable and enforces safety rules and regulations. Both the Building and Safety Department, as well as the Fire Marshall will be reviewing your plans. Good luck and keep us posted.