I believe the tap you need for the makerslides is M5x0.8.
You will also need:
-T25 driver
-1.5, 2, 2.5, 3, 4 mm allen keys
-Miniature screwdrivers
-Like @KellyHickel said, blue loctite.
I highly recommend 16, 18, and 20 gauge ferrules (and ferrule crimper).
I’ve put out a couple videos you may be interested in, specifically Assembly Tips and X-Axis Modification: X-Carve Maintenance/Troubleshooting Videos - Add Your Own!
If you’re going to stiffen the Y axis, you can see how I did it in this thread: Y Axis Braces and Belt Dust Shield