Has anyone installed a Frontpoint system in an old house, a large house or both?

Hi, r/homesecurity… I could use your thoughts:

I am in the US and shopping for a (preferably) DIY security system with monitoring that provides a certificate for insurance. Frontpoint looks perfect but I’m concerned about its wireless range.

The house is a custom designed 1948 colonial. The walls are plaster & lathe with metal diamond mesh. The house also has a complex air handling system and was built with six bathrooms, so lots of piping and ducts in the walls, all metal. Getting reliable WiFi throughout the house was a challenge.

Questions:

1. Anyone have any views on the range or signal strength of the Frontpoint hub & sensors? Would particularly like to hear if people had range problems and found a solution.
2. Is there any way to use two hubs or boost the signal if it turns out to be insufficient? I called Frontpoint and they didn’t know of a way to do so.
3. While on the phone, the agent mentioned they have long range sensors but these do not appear on their website; he has to add them. Anyone know of any other “hidden” items?
4. How easy is it to add hardware from third party vendors?