I've always found livechat to be a great help. We have chatrooms where you're free to ask questions that may be off-topic on the main site. Specifically, The Loop Chat is where you can talk shop. If not active immediately we will get to your question eventually or at least point you in the right direction.
WordPress also has their own IRC Channel to talk shop in.
There's the Official WordPress Forums where you can ask more long formed in-depth questions. They have a whole section dedicated to Advanced WordPress Development where your specific question sounds like it may fit in best. Their guidelines are much more loose than ours here and their forum based format is better suited for discussion.
Finally, you may want to check your local area for WordPress Meetups and WordCamps where you'll find professionals to talk to in person regarding the specifics of your project. WordCamps and Meetups are a great way to bounce ideas or talk best practices with people working in the field who may have run across the same bridge you're looking to pass.
For the most part, Stack Exchange is largely a QA format and the chatrooms are meant to cover everything in between.