Marlin Manual Mesh Levelling Test

I have been looking forward to Mesh Levelling as I havent had great success with the standard Auto bed levelling.
its in current form its a Manual one time process.
I set marlin so it measures 5x5 points (25 points) across the heated bed
I use a Feeler guage at .2mm

Once you enable it a menu option is shown. to Level bed
the printer will Home itself and then proceed to the first point.
you then use the control dial to adjust up and down the Z axis until the first point has the correct gap (based on the feeler guage)
you then click the control and the printer proceeds to the next point. until all 25 points are done.. it took me about 5 minutes to get it all measured up.

You do need to try and be as consistent as you can. with how you determine how close the hotend nozzle is to the feeler guage. I based it on amount of friction and effort required to get it under the nozzle once removed. I also had more success using a .2mm guage vs a .1mm guage
The adjustments is super fine. I had it set to move in .01mm increments

After it was done. I did a test I printed a 200mm x 200mm solid first layer. I have never been able to successfully achieve an even first layer of this size. my bed is 300x300

Here is my measured results from the mesh calibration. as you can see the bed isnt flat. even tho i use a Alum Bed, plus Borsilicate Glass plate and PEI plastic
The mesh defaults to a 4mm height. so above and below that show a adjustment.

I also preheat it for a while before i start measuring

SENT: G29
RECEIVED: Num X,Y: 5,5
RECEIVED: Z search height: 4
RECEIVED: Measured points:
RECEIVED: 4.29000 4.50000 4.58000 4.72000 4.76000
RECEIVED: 4.10000 4.40000 4.62000 4.78000 4.90000
RECEIVED: 4.06000 4.48000 4.92000 4.90000 5.08000
RECEIVED: 4.00000 4.37000 4.68000 4.98000 5.12000
RECEIVED: 3.92000 4.36000 4.70000 5.02000 5.20000
RECEIVED: ok

Checkout this first layer. 200x200mm .2mm layer. its beautiful!

it worked amazingly well. really well.. so well i may never go back to using Auto bed Levelling.

Attachment 8087