I came to a common base using the tax exclusive rate, consistent income, and consistent consumption.
And I incorporated you computation for a final analysis in the tax inclusive base for comparison with the others. All rates were expressed for comparison purposes as a percent of gross = taxpaid/grossincome which is what a tax inclusive base is.
In none of your calculations did you keep consumption consistent.
So? You did, I compared it with the others for completeness.
How can you compare an income tax vs. a consumption tax if one of those factors is changing?
Simple calculate amounts just as I did, last step convert to the rate system required using proper divisor.
Use the range of value the variable factor may assume and build a table of max , min, and typical expected value.
So go for it. You are the one who says people can compare everything in sales tax terms, that everyone relates to.
I want to see your comparison and work providing the answers in a sales tax, tax exclusive base. Make the base = nominal taxfree price basis
100* total_taxes_paid / nominal_base_price in the three scenario's requested will be sufficient.