I don’t believe CF can load balance based on port, unless you’d like to take to Enterprise sales.
Also, this is bad failover strategy since the entire machine’s network stack could go down, or the machine itself could go down, making failover itself fail.
The reverse proxy server can become single point of failure. Hence we are looking at some other robust bechanism. Please let us know if upgrading to any other plan would help.
Also if any of the community members have implemented load balancing for non-standard ports.