You're welcome to copy the spreadsheet for your own needs. What you probably want to be looking at is not that page anyways, but the economics page - seagulls are about the most expensive thing you can fire out there, but if you want to take down the gunship, you'll probably need them. The gunship should carry plenty of loot, so you shouldn't worry too much about breaking even on it. I didn't make the spreadsheet to min-max/optimize; that's on you if you want to do the calculations.
If you can, manufacture the spike rockets. Cost per damage is much better for manufacturing.
