In the 200 Response there is a field called "x-luminati-timeline".
The time in the field is the latency between the last IP and the site. You can use that to measure up to evaluate IPs.
Some fields and their meanings:
- z20822-init:1 - time to initialize the superproxy (load balancer)
- auth:80 - time to process authentication
- dns_resolve:22 - time to resolve DNS
- p2p_init:78 - time to initialize tunnel to peer
- p2p_conn:97 - time connecting to peer
- response:92 - time awaiting response
- dn_1b:0 - remainder of fields are breakdown of transfer size, dn_1b:0 means that the 1byte field was 0 for this request