Have you used the “Set Focus” tool under the 3-dots icon? It will let you set the aim point for the red focus laser – no manual focus settings required. I find that aiming for the left half of small objects yields a better focus result, but YMMV.
If you go the manual entry route, be sure that you are entering the difference between your nominal crumb tray height and the overall thickness of your blocks + spacer.
Added: making a jig with a top surface even with the top of your blocks will make it easier for the GF to focus at that level. I have one I made for dice and it solved my issues.
If you have the correct measurement, just enter it manually in Focus Height.
Set Focus is horribly inconsistent and takes forever. The machine will, unfortunately, still do an “autofocus” before the start of the print even if you’ve manually specified the material thickness and focus height, but at least you know you’ll have the right value.
I am doing ROYGBV blocks and have started targeting the yellow blocks.
Interesting the laser is measuring the height now, and lets me print, but still telling me it didn’t measure height. sigh So maybe the light blocks is the fix, and i didn’t notice before b/c i saw error message.