Greasy Fork

Which AutoPager Firefox Extension are you talking about? I can't find one on the add-on store. Are you talking about the userscript https://greasyfork.org/en/scripts/419215-%E8%87%AA%E5%8A%A8%E6%97%A0%E7%BC%9D%E7%BF%BB%E9%A1%B5?

Also, does it work well with Pagetual?

Yes, I am using Pagetual.
And Ewh is still compatible with Pagetual and any other autopaging tools. Just follow the manual of Ewh and go to its Advanced Config, set "What auto-pager tool do you mostly use?" to "Other". And done!