Thanks heaps.Not really "good" pictures, but a quick search makes me think, that the B-36 only rarely showed its full gun
Pictures from: B-36_01: Meyers K. Jacobsen "Convair B-36 Peacemaker"
B-36_02: squadron/signal N°42 "B-36 in action"
B-36_03 & 04: Meyers K. Jacobsen "Convair B-36 - A Comprehensive History of America's Big Stick"
Maybe interesting the caption of _02, saying, that the cover of the forward turrets was left open during take-off,
as an additional way out in the case of an emergency.
Say hello to a bucketload of drag when you extend those - given the cruising ranges they were going for, no wonder they didn't want them "always out" like on the B-29.
Are those pairs of twin-gun turrets side by side? Certainly looks like it.
I suspect that level of gun armament could have given a fighter a difficult time in rarefied air.