You can message me directly too at any time. I have a similar situation which the app is both a GUI and an API that services over 1200 different branch locations in the US and Canada with something like 2000 users. It runs like a top. I have a 4 core server running haproxy and three instances of the Xojo app on RHEL …works like a charm. So have faith you will get it, it is definitely doable and will work out for you in the end!
As I said before, if you search the forum for “load balancing” and “haproxy” we have had several discussions on this topic. You are not alone 