Help me understand the Acceleration settings

[printbus]

So it will always default to the lowest value? So if my DEFAULT_ACCELERATION is less than whatever I put in for the four value for the DEFAULT_MAX_ACCELERATION it will use the lowest one?

Yep. If you want to experiment, I'll offer the gcode snippets in the LINEAR CONCENTRIC SQUARES TEST post in the Marlin Motion Related Configuration.h Settings for MakerFarm i3v thread. They provide non-extrusion movements that can be used to observe the printer over a range of distances at both printing and movement speeds. I provide gcode there for both the 2014-era MakerFarm defaults and the tweaked values I settled on via testing. Use a text editor or an integrated gcode editor like that in Repetier Host to tailor values in the gcode commands as you wish.

I found the concentric squares approach very instrumental in learning how different acceleration settings affects the movement speeds achieved over various distances.