The few FAL's I have worked on needed barrel shims to get the proper timing.
The bolt when locked should bear against the breach not the cartridge head. The reason for that is to avoid cartridge compression on ammo that extends out the chamber a bit but otherwise seems to headspace. Therefore check your barrel vs the bolt with a guage or round first to see if the round or guage separates the two.
On a 16 TPI threaded barrel one rev of the barrel equals 1/16 inch axial displacement. Therefore a shim of less than 1/16 inch may be needed to get the barrel timed. Sometimes a tiny bit off the shoulder will do the job.
Marshal Tool and Supply Corp has the 1 x 16 TPI tap (p/n 2144-0401) listed @ $49.03 each. Metric FAL barrel sizes HSS taps are a few bux more.
Can you tweek the warp manually (arbor or hydraulic press) from your receiver casting ??? The steel is supposed to be in the soft condition.
The FAL ejector block is the BATFE control item. A semi-auto only E-block will be needed.
I'm looking forward to your build.