I ended up going through 2 Helder switches before having success on the 3rd try.
The first one broke before I even installed it, just cycling the switch on and off. It appears the plastic is quite brittle.
The second one I installed slightly misaligned. It broke after a few power cycles once the gameboy was all closed up.
The third one I have been using for a few days so far and it seems to be working well.
Make no mistake, it is definitely not as high quality as the original switch, but to my knowledge there is no OEM replacement. Also note, when installing the switch, make sure to follow Helders instructions on his site. They include a picture that shows exactly where the switch must be placed. It seems even 1mm off will not work correctly in the shell.