Suggestion for that problem -
(a) do the loading sums and determine a CG and weight value for the required load configuration - same as a longhand calc
(b) determine the forward and aft limits at the weight in (a) from your table/equations for the envelope
(c) do a simple comparison test to make sure that the calculated CG in (a) is aft of the forward limit and forward of the aft limit as determined in (b).
Plotting a picture is fun and makes the screen output pretty but doesn't necessarily achieve much beyond what a basic calculation will do for you. The aim is to keep the CG and weight inside the approved envelope .. how you do that is up to your imagination.