I made up a chart for my most-used print sizes: 4x5, 5x7, 8x10, 11x14. Just multiply by the factor from the chart and add or subtract contrast as indicated.
But, it's been months since I did all that. I don't even know where my chart is. I think I tossed it out.
Since I got an Analyser Pro, I don't putz around with that stuff anymore. I just take two readings then push the "Print" button.
Seriously! Pull your Christmas gift card money together and get one!