Consult a competent, licensed, bonded, and insured electrician.
Step two: What kind of risks do you face? Are you in an earthquake prone area? If so NG may not be a good bet. If the threat is primarily weather (torndadoes, etc) NG may be the better choice.
Dual fuel is never a bad thing. Options are ALWAYS good IMO.
I think once you answer those questions you'll be on a better decision tree. Just my opinion of course.
Good luck.
What we have is the 30kw Kohler whole house that handles the surges of HVAC and Appliances with ease.
I went with the LP fueled version as I can store that fuel forever and due my same considerations you have with storms we figured the LP stored on site was the best choice.
NG lines will be ripped up and shut down with ice storms and tornadic wind storms tearing down / uprooting trees. Fuels like diesel and mogas need treatment for longevity.
A farm tank or a few 100 pound RV tanks can be easily stored and plumbed to your whole house genset of choice.
A local electrician can wire this directly to a switch that connects to a 300 amp service.
Yes it is the caddy of systems and there ARE larger ones at the site I linked.
The poor boy version we have in reserve is a honda 7.5kw mogas rig I have had for a few decades that we plug directly back into the homes power supply through the 220 dryer outlet with a custom cord we made w/ 2 male plugs.
In this case it only handles minimum lighting and our freezers and fridges as it WILL NOT cover the surge of HVAC or small window unit Air Conditioners.
We use a small glass door wood stove for winter heating and open the windows and use a few box fans an open windows in the hot summers with that rig if the wood stove and oil lamps aren’t enough to get us through a power loss of commercial and our 30kw whole house genset for what ever reasons......and we have to use the small honda genset.
The Kohler whole house 30kw is installed on a pad in a enclosed courtyard and is pretty much maintenance free in the past few years and works well.
Cost for this Kohler 30kw flavor was 8.5k$ in 2008 and now seeing it go for 10 to 12k$ installed.
WARNING !
If you do install one ......let your utility company know as it is possible to feed power back up the line if switch is not proper etc ... don’t want to jump start a lineman per se. They will mark that line and power poles to indicate such a generator is on the line .......
Also I am building a battery backup system in the near future that will run a trace inverter for 72 hours and power the whole house. It stays charged day to day with AC trickle charger and will run everything including those appliances that surge if my plan is properly completed.
Last choice is just to teach yer lady about oil lamps, wood stoves, convection cooling, battery powered AM/FM or Sat-XM radio and books in case all the above goes south .....:o)
My 2 Cummins 4x4’s also have the 2.5 kw power inverters on em that lets me plug in an extension cord directly to the vehicles if needed.
Also have a dry ice making ability to top off chest type food freezers if needed to keep bulk product frozen till power is restored or food is consumed. One can augment the freezers long term freezer ability by freezing water bottles and keeping em in the freezer to keep foods frozen longer if ya leave doors closed during a power outage.
Just what we do........
I wish you well.......Stay safe !