Set the heaters as high as you can without buckling the material. I print with the heads high all the time. Select the profile and print. I prefer matte banner, print bi directional 720x720 dpi. If you get banding because ink setting too fast lower the fixer heater. Generally 45 degrees by 45 degrees is as low as you will need to go.
Optix is good material and I have used it but I prefer Ultra Flex.