I have been designing Executioner IIs since I first saw the "mk1 omnis" many years ago.
First I can't post anything because then they can't be used in TROs.
Next, FL doesn't work on Executioners. FL is roughly equivalent to FF unless you use 90% armour or more. At the same time it has a much higher crit cost. The Executioner is no where near max armour and increasing it will cut into the already limited pod space while the excessive crits prevent using endo steel.
The most effective Executioners I have built cut the HS back to 15 internal, installs ES, pods the JJs, and increase armour to 28x.
In addition to that I have played with endo composite, XL gyros, small cockpits, and CLPS. XXL, IJJs, and composite structure aren't worth the effort. Too hot, too big, and too soft respectively.