per Nick Thomadis: " Probably you mean the "Long Range Accuracy" (?) because most secondary towers, except some tall or late tech towers, do not have Long accuracy rating. " [I couldn't quote this portion of your post]
Rear Tower I: +4 Aim Speed, +2 Base Accuracy
Rear Tower II: +4 Aim Speed, +4 Base Accuracy
Rear Tower III: +4.5 Aim Speed, Base Accuracy not listed
Is Base Accuracy the same as Long Range Accuracy? I couldn't find anything which says what statistic affects what accuracy.