Hi Saran,
The relationship between Kepware and ThingWorx Composer is NOT one-to-one; it is many ("N" number of) Kepware servers to one ThingWorx server. In other words, a ThingWorx composer environment has access to any Remote Things configured within the associated ThingWorx server, and each Remote Thing can represent data from diffrerent connected instances of Kepware servers.
I hope this helps clarify things.
In general NO, you would not want to use a load balancer between Kepware servers and ThingWorx servers because the connection between Kepware and ThingWorx is stateful and maintained. Load Balancers deal best with stateless HTTP requests because each request is more or less stateless, and so if the Load Balancer reroutes a particular request to a different server, there is no "connection setup" other than a TCP socket that must occur before the request can be answered. For multiple path / not single point of failure in the network between Kepware and Thingworx, better is to use NIC teaming on both the OS running Kepware and the OS running ThingWorx so that multiple paths of communications are possible but managed by the internal operating system. We can discuss more on the phone after you engage my team by emailing presales.support@kepware.com.
Thanks,
Sam