AC questions for the experts

I remember them selling the retrofit kits and all they had was the fittings and a container of pag oil. Now I read that the expansion valves are different for 134, etc etc.
I know the oil is not compatible, the old ester oil wont suspend in the 134 or something like that.
Im still curious to know if the R22 will work in this. Although I might be better off selling it. They cost around $500 for a 30lb cylinder.