I had a lot of help on this from different tutorials and stuff.
https://mlp-vectorclub.deviantart.com/has super awesome tutorials, specifically this one https://mewtwo-ex.deviantart.com/art/Illustrator-Stroke-Width-Tool-Tutorial-365574608 by https://mewtwo-ex.deviantart.com/ who had been very kind and helpful to me
and this one https://sircxyrtyx.deviantart.com/art/Illustrator-Pony-Eye-Vector-Tutorial-287369345?q=gallery3Amlp-vectorclub2F36301008&qo=3 which is part of a larger series by https://sircxyrtyx.deviantart.com/
I also happened to find a youtube video that went step by step through all this https://www.deviantart.com/users/outgoing?http://www.youtube.com/watch?v=H8NurNF0kLc&list=FLAj6bWv_gOXjo9-08hs7Ing&index=1 it’s really long, but if the other stuff isn’t enough this may answer some questions.