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If you want to build a spreadsheet for this the formulae for the fore and aft c of g limits are not in the POH. You can get them from the Type Certificate Data Sheet which may vary with each model. The aft limit is quite simple as it is a straight line. The forward limit changes with increase in gross wt.
I have run several scenarios for an E model and it's very difficult to get it outside the limits. Max weight in luggage compartment and very light pilot might bust the aft limit otherwise if you load as per the weight limits at each station it stays within the limits.
You will need to alter the attached spreadsheet for your aircraft and make sure the results match the POH method before relying on it.
I have a version that will run on your iPad, you just need to buy the "Numbers" ap.