in my experience, the gun placements don't matter as long as the gun convergence is set correctly. Again, this is from my own experience. You can adjust the convergence of the guns to what you prefer. In my case, I set the GVF Shu to 400 or 600 meters, I forget which. You would think all are set accordingly the same, but they are not and they should not to begin with due to the different gun placements on a given fighter.
I have no idea what the convergent is set for the GTF Hercules Mk III, but once I ever get to that stage to adjust them, I'll have them tested.
Jadehawk.