Kyle,
At the link below, click on Sheet 2 at the bottom and there is a stuff sack calculator that might be helpful.
https://docs.google.com/spreadsheet...h2SzhwNWtaa0xFTEQ1NGZkckE&usp=drive_web#gid=0
J, Nice Job, looks great. Like your idea of the funnel shape, should work well.
Brad, do you have that spreadsheet in Excel .xls form?
Hunt'nFish