All of my stuff on C-More has been pretty basic. Single page, a ton of indicators, a dozen "indicator buttons", some diagnostic info, real-time timer, etc. I've never used more than 100 tags in a single page I don't think.
But what I did just think about, I've never deployed a single one over ethernet. They've all been RS485 over CAT5. Maybe that has something to do with it. Our customers are about as cheap as they come (it's a very, very low "bar of entry" business) and I can't ever get the budget to work with anything outside of the Micro's or non-ethernet EA9's. Which is the exact reason why I'm playing with AHMI. I'm going to build an interface and test it on a RPi Touchscreen system (which I rather like as they make a nice desktop case/stand for it), or a 2 in 1 tablet. Have you tried to run these over wifi? While I dread all things wireless, we have a customer requesting a wireless solution, preferably tablet. Thankfully, it will be the only device on the AP.
I'm also awaiting one of the 10" Chinese HMI's. I've been playing with their software and some of it is easy, but other parts are a little rough to figure out and of course, there isn't much in the way of help on them.