A DC-9-32 weight and loading chart. How to find the CG in % of MAC?

[john_tullamarine]

I assume that chart is for only one flap setting

Correct

On ours, we get the MAC off the top of the graph then extract the Stab trim from the above table, depending on the flap setting.

Quite standard. Generally, it is simplified by having the table shown recast so that it is integral with the trimsheet and one just runs into the table via the MAC value and interpolates for the stab setting. Given that the need for super accuracy is not all that critical for stab setting, this is more than sufficient for operational use.