Look at my build under the reverse flow section. Its titled 500 gallon smoker with 150 gallon cooker. See if thats what your looking for and i can try to answer any questions you have.
Buying plans is a good option. I didnt buy them but they sound pretty nice. Especially since you can call someone if you have problems. Plus you cant beat not having any guess work going on.
My thread is long on my build. Getting close to completion. A set of plans would have helped. Frank didn't have a set for my size tank at the time. A custom set was 6-8 weeks out at the time. I have made it thru the build with a lot of help from guys on here! With plans you get even more support. A direct line to ob1.
Good luck! If you decide to go without plans, we will help all we can. But I would definitely recommend to buy plans if they have a set that's fits your build or if you do not mind waiting on customs...