Scaling: Rancher 1.x vs 2.x for huge number of hosts

I have a need to control really huge number of small hosts with Rancher (I expect thousands, say, 5000 hosts) in dynamically allocated cloud environment. Each host runs rancher-agent and only few services. Each service uses own IP, that’s why high number of hosts required (or few IP per host, but most VPS providers only allow up to 5 IPv4 per VPS).

Currently I use Rancher 1.6 (Cattle) and found that resource usage grows high when I have 50+ hosts. 50 hosts require near 2.5GB of RAM for Rancher server and some CPU ticks.

The question is: can Rancher handle 5000 hosts, and what resources it may demand for that? HA/load balancing will be used, but I think each server instance still has to control all hosts and share the same SQL database. Anybody tried/use such huge setups?

Another question: is Rancher 2.x better in this regard? I like 1.x since it looks like less demanding, but maybe 2.x can scale better?

Please give me ideas if this can be implemented using Rancher at all.