Don't depend on Aircover.Homeowners policy will not protect you if your renting as a STR.You need the correct STR policy to protect your property.

Just a builders risk policy if you are doing an extensive rehab on the property and then a landlord dwelling policy when the property is rented.

I am currently with State Farm but they will not renew the policy after May 2025. 

I am not privy to the details of that from their perspective, but I would hesitate to assume the policies are the same; I don't believe they are.

I find it's very personal, and dependent a lot on your goals, resources, risk tolerance, location, experience, etc.

You want this to be your backup plan if things take longer than anticipated, you do not want to dip into personal credit cards so i would use a heloc to help with down payment but try to keep a nice available balance on a heloc as your insurance policy. 

What is your risk tolerance?

If you have not already purchased this policy, I would look for a policy that provided a stated amount deductible for wind/hail vs. a % deductible.

While I could have gone lower I am lowering my risk tolerance because I expect a recession in late 2019 to 2020.

Tolerance for value-add?