I have settled with the "Moski" CNC 1310 as it features direct drive and 10mm Aluminum components.. although for all intents its the "Deluxe" Eleksmill. This features an M3 thread in the top support plate. I have purchased the Eleksmaker 2500mW Laser, found a similar issue in terms of securing the laser.
There is a little margin around the mount, I have simply shimmed this with thick card to center it and made reference marks on the Y-Axis table to ensure its centered.
Remember any slight movement will throw out any precision etching.
Hope this helps.