About Https monitor
I would recommend not using just a simple GET , but GET index.html for example, or whatever you have on the webservers.
Then if you want just to do a simple check you live it like it is : RESPONSE: HTTP/1.1 200 OK
Or you can use Receive String to check for a specific word in the HTML reply. The text string can be regular text, HTML tags, or image names.
Then you can use the Reverse setting to Yes, the monitor marks the pool, pool member, or node Down when the test is successful.
As for the host part, it should be your web server domain name, like www.example.com.
All your servers should have one and it should be the same.
You attach this monitor to the pool, so all members in the pool will use it.