You can use a magnetic vernier wheel on the front and replace the front trigger pin with a non-plated set screw that will attract it. That's the easiest route to take. Results in a fairly snappy trigger pull that can be a little heavy depending on the magnet you use though. You can install an opposing magnet at the rear of the trigger paired with the rear magnetic vernier wheel as well, but that does require more modification to the trigger (you need to use an end mill bit to drill out a pocket for the magnet and then epoxy it into the trigger).
Any idea where to find a non plated set screw? Also, is there any way to get rid of the lateral trigger movement? Maybe by putting washers on both sides of the trigger? Big thanks to you, Dr. You're always very helpful.