Dont stress the zeroing set up. Its a one time set up, simply fit, shoot, measure the distance of impact from point of aim then adjust the appropriate axis the correct amount, shoot to confirm.
The repeatability when you take it off and refit it is very good once you come to grips with it. Rusan have a good demonstration here.
https://www.youtube.com/watch?v=ykI3rj0qMI8
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