This was a quick project you dashed off for your portfolio- ask for a reasonable royalty, in line with whatever they typically pay (probably under 5%). Hourly billing is a dismal business. I’ve hated it every time I’ve had to do it. Not knowing anything about this company, their volume, or their price points, I am going to guess a wholesale price of $25. At 3%, you would get $0.75 per vase sold. If they sell 2000, you’ve made $1600. If they sell 20000, you’re making Taylor Welden kind of money. If they sell 200, they probably shouldn’t be in the business of selling $25 vases.