Offline Listening Question

[twixcabrera]

Plan

Premium

Device

 Samsung Galaxy

Operating System

Android Oreo

My Question or Issue

I will be a little bit off the grid due to offshore work but will make it online couple of times in a month but with a very very restricted Data Cap which usually around less than a GB mostly consumed for messenger and emails. After downloadling about 10GB of my playlist, how much MB does spotify consume to maintain my offline playlist given that im subscribe on premium for a year. Im hoping its usually less than 20mb or so for a simple script file or what ever you call it. Thanks!