Insurance for 16 YO learner's permit

My oldest turned 16, we're going to be pushing him to get his permit. Has to have it for a year before he can get a license.

Right now, two drivers (my wife and I), and four cars. She dailies a 2014 Mazda 5, I DD a 2004 lancer Ralliart wagon, we have my 88 Silverado for truck stuff, and my 99 Miata sport is autocross only (but no trailer yet, so it has to stay registered and insured).

If we add him to our policy, I've got a big increase to cover four cars. My wife suggested that we change insurance companies with one vehicle so that we can just add him to that car. 

Does this make sense? Is it even possible, or do I have to cover him for every vehicle, no matter what?

Depends on the State you are in, in most States, you do not need to add them until they actually have a license. Many companies also look at all of the registered vehicles, so changing companies for just one vehicle will not work. Have you asked your company?

Same deal in Ohio.  While on a learners permit, the youngun is not on your policy.  Only when they pass the test and get a license do you get to enjoy the massive price increase.  It cost us $850 per year to add our daughter this summer, and that is with her limited to only being covered to drive the liability / uninsured motorist covered 2006 Civic, with good student discount, and Tire Rack Street Survival class (highly recommended btw!) discount.

Yes, you can put just one vehicle with another policy.  You'd still be required (most likely) to inform the insurance carrier for the other 3 that he lives in the household and has a license.  However, you can show them that he has a car of his own which is insured.  Nobody here will be able to tell you costs.  That's 100% unique to your situation, so anyone elses experience may or may not have any relevance for you.

I did not think about this when my kids got their license.  USAA had them driving my mustang.  We only had five cars then.  I had to go through the list and designate who drove what car.  My life insurance guy told me that the insurance companies flat out don't believe that your kids will never drive any of the cars in the stable.  But they will let you designate who drives what.  Like what was said above, these things vary by state.  I do know when I did think to call them, I saved money  by getting the youngest driver off of the mustang.  I have no idea which cars would make my bill cheaper, buy my son is driving our old fox body and my daughter one of the miatas.   It was nice to not have the increase while they had permits.  

I would be curious to see how you make out.

In reply to thedoc :

I try to be good about following up.

I'm so overcome by events  I feel like I'm living life on a  surf board.  I shudder to think where I would be if my wife wasn't paying attention....