Here is my $3.82 LCA press that worked great.

 

As simple as that 👍

It looks a bit like my slave cylinder compress tool; two long bolts with a piece of wood with a small notch for the tip.

 

I take it you're not in the rust belt

This was just to pull the new ones in, right? You cut out the old ones, then? Thanks for sharing your solution!

 

​​​​I'm in the rust belt, why? Yes, I cut the old ones out with a sawzall and used this to press in the poly replacements.

 

I didn't cut out the old ones on mine, I tried using one of the on-vehicle removal kits. Unfortunately, the tool wound up stripping out, even with liberally applied grease to the threads of the bolt. More detail here.

In my case, I wound up lowering the front subframe to complete the job.

Ah! I see from your reply that you went with poly replacements - that's why your re-installation went easier than what I struggled through. Our R52S is my daughter's car, so I wanted to keep the pliability of the rubber bushings. Glad it all worked out for you!

 

​​I almost did end up dropping the subframe myself because the inner ball joints needed replacement. Total pita job but doable with both axles out of the way. Getting the control arms into the poly bushings was no picnic, how did that go with the OEM style bushings?

 

While my 'off the car' method for pre-pressing new powerflex CAB into the carriers may not be consistent with the (on the car?) OP's DIY approach...
This was my 'apartment dwellers' / poor man's answer to an improvised press...

I sourced and pulled a pair of front LCA carriers from a salvage yard Mini and cut out the old worn bushing via the saws-all and chisel method.
I had read beforehand that the subframe could be lowered part way to allow enough access in removing the old control arm carriers and replacing them with a set of pre-pressed.

 

Because I had the bushing brackets off of the car/subframe, I was able to push them on with my press before re-installing the control arms on the car. I thought I had a picture of the process of how I pushed the bracket with new bushing onto the control arm, but I'm missing that. Here's a pic of pushing out the old bushing from one of the brackets.

 

Ooooh - Nice little press set up you have there @khnitz !
Envy.