Like Keith's, on the RF smoker I built, my collector was not huge - only slightly larger on the top than the stack...although I put the opening for mine slightly higher - closer to the upper rack that the lower one. And exactly the same shape as Keith's.
I should say - that design was not mine, but from a set of plans I got from the pit builder I was taking about earlier.
Here's a pic that shows where my smoke collector was in relation to the cooking racks:
View attachment 694513
I only built a fire in it twice before it was sold...but ran great and held pretty consistent temps across the CC. It's now owned by
Brokenhandle
. He'd probably be happy to tell you how it performs if you asked.
Red