I had troubles getting a cylinder off of my honda. My mechanic friend had me tap it with a hammer on the side with the fins with some wood and after so many POOF the cylinder slid straight off and over the piston. On another case I had laying around I had trouble getting the piston through the cylinder, hopefully you don't have trouble with that.
As for shops, I have not used either but according to this - you can use any honda 50cc rings ["Hobbit, NC50, NA50, NU50, NX50, etc."]
$10 + Shipping honda hobbit stock chromed piston rings set - 40mm x 1.5mm
The other moped shop 1977 Mopeds does not have any stock rings for some reason but a good shop to know about nonetheless
Hopefully that helps. You should order up a set of new gaskets -- Base and head -- too I guess since they are reasonably priced.
Be sure to make sure the cylinder looks clean also. Otherwise you may want to order a Piston + Rings $30 - If it is scored get the 44mm and get it bored haha
How many edits can I do! (edited)