Having done more than a couple of these jobs on both 124 and 201 cars, I do it a bit differently precisely because of this issue. The stud has to line up near perfectly to get things together correctly, that can be a real pain sometimes. It sounds like more to do up front but it often works out to be less in the long run.
I free the entire wheel carrier up. Disconnect the ABS sensor where it meets up in the engine compartment, dismount and hang the caliper. Disconnect the brake pad sensor wiring and the ABS wiring from the clips holding them to the shock. Un-bolt the three fasteners that attach the shock to the wheel carrier.
That will allow the shock to swing out of the way and with that done the wheel carrier to swing downward and outward giving good access to the bolt securing the wheel carrier pinch fixture to the ball joint's stud. That way the bolt can removed AND whatever force might need to be applied to get things apart. That mechanical connection is strong, tight and here in the rust belt can be corroded in place. And impact gun can be used to get the bolt loose and removable if needed.
Once that's accomplished the stud can be very solidly stuck in the pinch fixture of the wheel carrier. If so, a pickle fork can then be used to force the stud out of the fixture some times. I have a small tool that mounts to the wheel carrier and forces a wedge into the cut of the pinch fixture and thereby spreads the pinch. (
https://www.ebay.com/itm/A-711-Hub-Clamp-Spreader-Tool-Ball-Joint-Shock-Strut-Steering-Knuckle-ASTA-TOOLS/222660647377?epid=1978636676&hash=item33d79bd9d1:g:3hcAAOSwJ41Zzj9g:rk:11:pf:0) I used to use a large cold chisel placed and hammered into the pinch cut to spread the pinch, until I witnessed another wrench doing the same thing probably too energetically and one side of the pinch fixture broke off.
Now I use the wedge tool on the pinch to get things apart and then leave it in place so it's easier to get things back together.
With the wheel carrier off the stud, R&R the ball joint or the LCA. Then you can rotate the stud to line the cut-out and tilt the stud outwards. With the stud in that position it is much easier to see what's going on, if things are lined up and you can much easier manipulate the wheel carrier into position to get it lined up on the stud.
Once the wheel carrier is on the stud I remove the wedge tool from the pinch fixture. Use a tapered punch to move the stud's cut-out into perfect alignment. Install a new MB pinch bolt, pack the pinch cutout with the thickest grease you've got. I live in the rust belt I always replace the pinch fixture bolt with an original MB bolt, small insurance for a very critical fastener in a very critical installation. Permatex Never-Seize on the ball joint stud and inside the pinch fixture.
Now you can sort of fold the wheel carrier into the upright position, compress the shock upwards and get the ears on the shock in position onto the wheel carrier and get the through bolt installed in place. The two threaded holes for the short 19 mm bolts below should be lined up now as well.
Get the fasteners torqued to specs, wiring reconnected, caliper reinstalled and you're good to go.
I usually put a spring compressor in place just tightened enough to take it's tension off the LCA, BUT I have done this task with the LCA blocked underneath assuring that the block you use is tall enough to allow the ball joint removal tool to get in position to allow the removal and installation of a new joint.
In this situation it's probably not worth it to take anything apart you'll just have to wrestle things into alignment in order to get things back together.
That's why and how I decided to do this R&R the way I do, I've been there and done that; but luckily I had the vehicle on a lift along with another pair or two of hands and pry bars that helped get things aligned in order to get things back together.
Oh yeah, KROIL on the fasteners for a couple days usually makes every suspension job a bit easier. You've really got to tug on those large suspension fasteners sometimes, a little lube makes life easier.