Sorry, those who know about the SNN toolbox are on holiday this week and many next week so it may be a while to get a proper answer.
The fact your code is still using spynnaker8/__init__.py shows me you are not on the latest master.
(Sorry I am not 100% sure how to change that)
I also think I remember something about their being a bug in relation to delays being a list but I can not remember how that was fixed to give you a solution.
Christian