Thank you vanepp for your time and thoughful input.
As luck would have it, I have a similar 43A motor driver which I could use. I hadn't thought of that. Thanks.That eliminates both relays and will enable soft start/stop function. Awesome.
I take your point regarding the limit switches. I guess I was trying to avoid large/bulky switches required to switch full motor current. I'm not sure how to configure them in the motor power circuit if I use the above motor controller.
Security is not a big issue since the gate is almost never locked now. Probably just knowing the ip address of the web interface would be more than I need. I intend to have a manual/mechanical override anyway. This whole idea is just a convenience so you don't have to get out to open and then shut the gate/s.
Temperatures here range from about 0c to 40c.
Great ideas here thanks vanepp.