I believe that harder pruning in the Spring will solve my problems. Internodal distances are greatest on first-growth wood that sprouts after dormancy. I really never pruned back branches. I always hoped buds would sprout further back from the older, 2-3 year old wood, and that my trees would fill out, and produce more fruiting branches...but that never happens. The branches just keep getting longer, and longer, and new growth is only from the terminal ends of those branches.
I think fig trees have very strong apical dominance, and must be cut back hard in order to induce branching from older, dormant buds. Look at any neglected fig tree. All current growth is located at the terminal ends of the branches, never from the trunks, never back from section on a branch that's 4-5 years old. The whole tree is bare wood except at the very ends of each branch where new wood has sprouted.
Let's say you grow a cutting for 5 years, and never prune it, and, never pinch out the terminal bud. Let's also say that it grew 1 ft. each year....at the end of five years, the tree is now 5 feet tall. Figs formed starting in year three, and continued every year thereafter. Now, it's year six. Where will main-crop figs form? They will sprout from the leaf-nodes on green wood formed in year 6, and not from older wood. This growth pattern will continue, and the tree will get taller and taller. If it branches, this pattern will continue, and each branch will grow the same way.
Next Spring my trees will be cut back.
Frank