Is your workflow Pinegrow > Pulse?
If so, would love to hear more about that. Maybe even a blog post??
@jenus ^ how are you trying to integrate into RapidWeaver? Would like to hear more about this also. And theme integration is something to be worked on so that it is much easier to work with any website builder.
But at the moment the easiest is using a handcoded HTML5 / PHP site based on any framework (Bootstrap, Foundation) and using a text editor to make your theme.
Or if you want to design with an app try Freeway and look at @TimPlumb's guide:
Or something like Pinegrow
Or use a theme already built:
Let us all know how it goes!