Mark Graham has discussed the work he does on trigger so that the layman can do it. The best that can be accomplished while having a safe trigger is to reduce the weight to a bit under 6 lbs. and make the break crisp, like a glass rod. Not ideal, but far from terrible. Not sure what DSA does. If done wrong, the trigger can be ruined and/or made unsafe.
I've seen some good results posted on the FAL Files with a StG-58 with a scope mounted using a DSA scope mount and decent ammo. The following was the result of shooting by FAL Files member stubdog25. His rifle is a very nice StG-58 kit built on an IMBEL receiver with a DSA scope mount and I think a U.S. Optics scope of some sort.
Following picture is of a target he shot that was 550 yards away. Ammo was Federal 168-gr. GMM. 10-shot group. Group size 9.75" (1.69 MOA).
Next picture is of a target at 715 yards. 10-shots. Same ammo as above. Group diametre 13.5" (1.8 MOA).
Finally, the next picture has a 15 shot group in the lower left target of German MEN NATO ball ammo at 100 yards. 1.7" group diametre (1.62 MOA). Groups were also shot at 550 and 715 yards with this ammo, with 16.5" (2.87 MOA) and 21" (2.81 MOA) group diametres, respectively (not pictured).
I forget some of the details, but an Italian FAL Filer was able to get sub-MOA groups a significant percentage of the time using handloads and iron sights. His rifle is a Lithgow L1A1 that he used to win at least one 300m service rifle match over there in Europe. He did more extensive accurizing work on it, though, some of it designed to mitigate the effect that having the iron sights on two different assemblies can have on accuracy if things aren't perfectly tight, although shims exist now to do some of what he did more easily. With a scope, this isn't an issue. I think he also got a new barrel made by Lothar Walther or something (or maybe found a NIW Parker Hale; I forget, exactly) and reamed the flash suppressor (although this was because it was off-center). Another thing he did was eliminate play in the rear sight and also a trigger job. Unlike some folks here, he did not attempt to do any work on the bolt/carrier fit. His handloads were tailored to this particular rifle. I recall that he found a bullet, powder, and cartridge OAL that was perfect and got him under 1 MOA part of the time.