What do you suggest for lubrication on the rails of the VLXL?

The X-axis rails on the Vertical Laser XL are the round rails found here: https://www.buildyourcnc.com/item/mechanical-rails-linear-guide-rails-20mm And use these rail blocks: https://www.buildyourcnc.com/item/mechanical-rails-linear-ball-bearing-block You want to use lubrication/grease for a couple of reasons. - The round rail, if subject to moisture, can rust over time. Most oil based lubrication will help prevent this from happening. - The bearings in the linear guide will be constantly in contact with the round rod of the linear guide. Grease with a NLGI grade 3 specification and one with a good adhesion property so the grease will remain on the surface of the guide for a longer period of time.