Very good work. You beat me to the circular turret technique. What I had in mind, and what I think you've done, is use one of those pipe pieces to create the perimeter and then clip on the pieces to it. You've got the dimensions right for minifig scale too. The ERA blocks are a nice touch. The only room for improvement is you're missing the fording snorkel in the stowed position along the side of the turret. The long-range fuel tanks are a nice touch. Also, your photography needs to improve to showcase this excellent MOC. In your next version, bring a lamp closer to where you want to display it so your camera has an easier time of focusing without a flash.