Need Help Question Printing white on Epson S80600

We just got this printer and figured the white out however we have a job coming up where they want different opacities of white. The only way we have figured out how to do it is through the printer setting printing one white opacity at a time running it back through the printer and printing over it with each different white they want. Does anyone know of a way we can get all the different opacities at once? Since it sees white as a spot color can we set the file up with different percentages of white and have it print all at once?
We are using Illustrator, Onyx Gamaprint Pro 18, and Epson s80600 printer.
TIA

 

We tried it and it does work! So thanks!! We were just thrown off by the fact you can set your Spot 1 to say purple and it will read it white wasn't sure if changing the opacity of the purple would be read or just the fact that it is the Spot 1 and just telling the printer this is white. Anyhow it worked!
But we primarily use CorelDraw and haven't been able to get it to work within Corel we are having to set-up the files in Illustrator and so far that's the only way we've gotten it to work. Everything else we do is in Corel.