What are you using for a load? I shot it over the weekend with a 575213 Minie sized at .575 over 60 grains FFG. I was all over the place but the Grand Canyon rear sight notch did ZERO for accuracy.
A couple further comments- on the rear sights, get this-
https://www.ssfirearms.com/proddetail.asp?prod=58S147&cat=87
Use in place of the awful issue sights. Don't forget to raise the front post as well.
Get an assortment of bullets to try from the only source I trust on the internet- here-
https://www.lodgewood.com/Bullets_c_7.html
Use only RWS or Scheutzen caps. CCI current production are manure for accurate shooting. They're designed for blanks and reenactors.
Ditch the Bore Butter. You can get Crisco or better yet, Lard at your local grocer.
Don't get hung up on the "60g" 2f service charge. Current production powder is not the same as back then. As for powder, I'm a big fan of Swiss but Scheutzen is also good. Try both 2 and 3f in moderate charges. We've found the the North South Skirmish Association that, in general, a moderate charge of 3f leads to best accuracy and less fouling. It also uses less powder meaning that pound gives more shots.
UToob is a HORRIBLE place to get advice on a gun designed to shoot minies unless you're very, very careful on who your taking advice from, but in that case, you probably already know how to shoot a minie accurately.
Here's a couple shots of my initial work up of the Zouaves we use in youth instruction-
Zoli Zouave, 10 shots
Korean Zouave