Bumping the caster up to 5° - 7° will make a night and day difference in how your car handles.
You’ll need at least 5° for it to be as effective as you want it, but since the shims are a set thickness at about 2° per shim you will use 1 or 2 shims to get you somewhere in that range. Since you already have about 2° in there, then they should be able to get you to 6° pretty easily. They’ll have to decide once the shims are in whether you’ll need the longer beam mounting bolts. They’ll want at least 3/8” - 1/2” of bolt thread engagement once the shims are in and that’s why you want the longer bolts - “Just in case” planning!
I wouldn’t get too hung up on camber adjustment. Unless you’re planning on taking your car on a track to really wring it out, the VW sedan spec for camber should be fine for normal driving. If they had had trouble setting camber then, yes, there are different camber eccentrics available that allow more adjustment. I have a pair of those, too, but I also used to get out on the track from time to time.
All of us (except the Beck folks) adjust our caster with these shims. Beck cars don’t, because the proper caster is built into the frame already (those clever Beck folks!) and the front suspension is a trifle different but the result is the same.