I am just too lazy to mill a skim coat off of my MDF spoil board. I wanted have a graphical check and decided to use an Amana 45º (90º) V bit I just love.
I used to cut 100mm grid at 2mm deep knowing that doing the math the width at the top is double the depth so 4mm wide, for 2 deep.
This gave a very quick “topographical” glance of the entire area.
It’s hard to photograph because of parallax but in person is easy to see and measure where it’s wider or narrower. I also like the groove for reference and if possible driving the hold down screws in the valley. As well as sawdust (or should I saw cutter dust )
It all comes down to what you use it for and how far off your table actually is.
I just surface my big machine I took 0.4mm off the surface in two passes. 0.2 took off a few really high spots, 0.2 more got most of the rest. I am left with a semicircle at the very front that is probably 0.1-0.2 low. I can live with that until I surface it again.
If you don’t deal with Z depth accuracy much it is no big deal at all. Through cuts don’t really care. Or if you do surface carves, and you surface your material first, same deal, no need for a perfect table.
I guess you probably know my stance on all this by now. I think a lot of people chase zeros because it is kinda fun, and we all want “perfect”, but when has it ever mattered if your drawer box, arcade, or house sign needed to be more perfect than 3-5mm?
epoxy inlays care, but that is the only time I’ve needed to worry about it. and only beacause the board will look funny if it isn’t leveled, but you can check that and shim it before you cut if you have to… or so I’ve heard.
