Logitech's lovely MX full-size mechanical keyboard unfortunately uses non-standard stabilizer distances on the right shift key and space bar. These printed adapters are designed to be glued to standard 3rd party keycaps in order for them to fit to logitech's non-standard stabilizers. These are self aligning, require only superglue and flush cutters, tolerate up to 0.6mm nozzles, and the results feel and sound as good or better than the other keys to my hands and ears. 

These adapters were designed around a full-size MX mechanical keyboard and XVX low profile keycaps with about 1.5mm of stabilizer protrusion and 4.5mm of stabilizer stem. I don't think the MX mini has the shift key issue, but I do not have one to confirm.

Print settings

I used a 0.6mm nozzle (curse you bambu and your hard to swap nozzles). Anything smaller than that should be fine. 

Arachne slicing if your slicer has it. 

The parts were designed for 0.3mm layer heights.

A higher durability and layer adhesion material like PETG is best. 

100% infill, but the parts are likely too small trigger sparse infill at all. 

Given the small features, some adjustments may be required as needed. For me, this meant increasing the max fan on my PETG profile to 80%, bringing the minimum speed down to 10mm/s, and printing both pieces at once to maximize layer cooling time. A little fine tuning with flush cutters may still be needed.

Shift key

This one is easy because it uses the existing stabilizer connectors as alignment features without any cutting or modifying.

First, print the adapter and test fit it on the shift key. The outer holes in the adapter should fit well against the original stabilizer connectors without the part bending or deforming at all, and the top of printed connector should be roughly level to the top of the original connector. 

Remove the adapter from the keycap and test fit it in the stabilizers on the keyboard. Confirm that the top of the stabilizers can bottom out against the bottom of the connector and the connectors grip the stabilizers well. Move the installed adapter up and down to confirm nothing is rubbing or binding. Now install the shift key over the top and give it a few clicks.  if anything doesn't fit or feel quite right try some some post processing, slicer setting changes, or dimension adjustments to the step files.

If it all fits well you can take the key and adapter off the keyboard and superglue them together. Take special care not to get glue on or near the center stabilizer. Leave the keycap for an appropriate time to cure.

Space bar

This one is trickier because the placement of the stabilizers overlap. To get around this you will have to partially remove the keycap's stabilizers before gluing the printed adapter in place. The cut is a little specific, so consider practicing on a key you won't use. Taking a few small cuts with a flush cutter is probably wiser than cutting the whole thing at once.

Take the space bar you are installing on the keyboard and cut the inner ¾ of the outer stabilizers off with flush cutters. There is a picture illustrating what section I mean. This section needs to be flush with the base of the key. Then cut the remaining ¼ at an angle up from the center of the stabilizer. This remaining nub will be an alignment feature.

For V2 space bar

Test fit the adapter on the spacebar keycap by sliding the center hole to the bottom of the center stabilizer, then press the outer holes over the nubs left by the original stabilizers. On my model this was a tight encouraging fit. If satisfied with the fit, you may test fit the space bar and adapter on the keyboard. If anything is rubbing, binding, or not fitting right, adjust as you did for the shift key.

If it all fits well you can take the key and adapter off the keyboard and superglue them together. Take special care not to get glue on or near the center stabilizer. Leave the keycap for an appropriate time to cure.

Once completely dry you are ready to put them on your keyboard!