HTTP Fallback option . Variables ? HTTP Profile

Greetings all

Long time lurker first time poster

Looking to use the http_fallback option on the http profile more effeciently

two questions

1) can we point the fall back option to an IP address on the F5 in order to have a globabl irule for creating a maintenance page with more data and more infomraiton for troubleshooting

2) can we put variables in the fallback line option of the http profile in order to get the same data . 

I have no issue doing either just looking to create something that is more robust when our systems are down unintentionally vs just a generic page. 

thanks

John