I read somewhere that there is a sealer you can put on street the Keda to protect against the UV. But i do now remember you saying that you choose another dye.
Top coat, I'm not sure - I have a cousin who offered to allow me to use his automotive lacquer. He lives about s half hour from me and does shift work so I might just use a rattle can (Watco I've heard is good). But I also want a good quality finish, so I may use what was offered. Still undecided to be honest.