Your roof has 4x8 sheets of 3/8 plywood covered with a rubber membrane... You will see where the sheets meet thru the membrane... There will be supports where the sheets meet and at two 16” intervals between sheets... I wouldn’t sweat getting screws into the supports - Worry more about placing the panel where AC/vents/TV antennas will not potentially shade the panel... Just use 3/4 stainless screws and cover with dicor to seal the whole z brace assembly... Also use dabs of dicor at 12” intervals to secure the wiring to the roof between the panel and the roof plug (do not add anymore dicor to the Zamp plug assembly)
A basic z bracket you will find on Amazon is fine... (comes with screws)
Also here is a generic UV protected plug/cable to connect the panel to the prewired rooftop Zamp receptacle
You will need a couple MC4 connectors to put on the end of the above cables to attach to the panels - But check and confirm your final plug wiring polarity to the charge controller when attaching the male and female MC4s
Buy a MPPT charge controller - Not a cheap PWM
Personally I would go with two 170w panels (panels are the cheapest component) and a Renogy charge controller with a Bluetooth dongle so you can monitor everything via a nice app on your phone...
Once your finished with the solar look into your “inverter prep” - you can easily drop in this transfer switch inverter... ;-)...