Need help with tires 87 V30 SRW

[OlRed87v30]

Hi all. New to the forums but have read many posts here, and has been very helpful in my endevours. I currently have a 1987 GMC 1 ton SRW RCLB TBI 350/400/205 4.10s. It sits on 315/75r16 tires but soon the new stock springs and new 16x7 wheels are going on it. This truck will be used for recreation, camping, hauling hay, farm, travel etc. I have a detroit trutrac in the rear and locker in the front being installed soon. I'm torn between 235/85r16 or 265/75r16. I've considered 255/85r16 tires and I have a pair of ORD shackles and 1" zero rate AAL. I've decided on either Cooper ST MAXX or mastercraft courser CT. Any help is much appreciated.