Sorry but don't have Idea how much will you earn since I don't have teir 1 countries on my followers hahaha but I think you will get a good amount of money out of it. Maybe extra $1000 or more a month if you post at least 1 video per day since you have 1.3M followers and you said its active so I think it will easily go semi-viral.
Still the location of your followers is a big factor for earning high as most of my friends say its a "premium page". oh and maybe you can apply for Instant Article as well.
NOTE: just be careful with violations it will ruin everything.
Here is one of the pages I'm handling,
Page Info
18K followers majority comes from tier 3 countries.
2x a day upload. (based on insight)
The owner of the page has a 200K+ member group. (quite active specially during weekends)
Ad Breaks only.
View attachment 145349
Hope this one will help.