Planetary Imaging?

I am going to use one of the www.CNCSUPPLYINC.com ultrawide adapters. I had originally planned on connecting my camera directly to the back of the scope by using the adapter. I am now thinking about incorporating a barlow into the setup as well, but am unsure how i would go about connecting it. Would the connection be:
Scope back-Barlow-Adapter-Camera?
Or do I need to add a diagonal?

You should not need a diagonal. I suppose there is some
chance the scope will not reach focus without a
diagonal, but probably it wil be fine.