I use online services like google docs quite heavily, and would use wix.com if I can get the performance to improve.
1. How can I tell if the performance I'm receiving is at or near the maximum attainable?
2. How can I identify a bottleneck if there is one?
eg I could try various combinations of different PCs and different internet connections, but is there any analytical way to find out?
I use windows 10, windows xp, ipad, and android devices, so can run diagnostics on any of these.