I am also in the same process at the moment , therefore I would like to know the answer for this question.
So far, I have managed to get service plans working in Kazoo 4.3 using the new services API documentation posted in github/2600hz.. kazoo/core/kazoo_services
I also managed to add a couple of rate documents in ratedeck database and I can see the rate to be applied using SUP command. However, cdrs still don't show the call being rated. For this part, I used https://docs.2600hz.com/sysadmin/doc/kazoo/call-rating
Finally , Jonny5, after setting limits document for my test tenancy, installing kazoo-application-jonny5 and loading the application Jonny5, I still can't find the way to limit calls by balance run out, or any other type of limit. For this bit, I am using this https://docs.2600hz.com/sysadmin/doc/whapp/jonny5/
I hope we could share information and figure it out