If the Wall is as blemish-free as you state, I would not advise trying to experiment with "rolling": as every time you touch a Low Nap roller to the wall you risk introducing either roller marks, runs, drips, or sagging, as well as unwanted texture. Or worse, any combination of the aforementioned. Correcting such things can be a problematical effort at best, and wholly ineffectual at worst. The PJ can be a spotlight to reveal every mistake you make. And ....with your Room's color scheme, You could never be happy with any "White" surface, so that would just be a exercise in futility.
So at this conjecture, why bother to spend the time, money or take such risks?
Spraying on "anything" right from the start assures one of the best possible chance to achieve a perfect surface...or as nearly so as a person can achieve.
BTW, no chance at all that a BOC Screen unpainted could ever match the performance and image quality a painted "hard & smooth" surface can provide.
In your case mjbrowny21, unless you can consider changing the colors of the room (Ceiling -and- Walls), even with effective light control you must use a paint solution that will combat the effects of the Screens reflected light being collected by those surfaces and bouncing off them, lighting up the room like a giant light source (...which it is, exactly.) and washing out contrast.
So lets examine your choices based on the inability to change the Wall / Ceiling colors.
Much depends upon the size screen you want as relates to the height of the wall it will go on, as well as the proximity of the walls/corners to each side of the screen. Please provide a few extra parameters so they can be taken into account. Include your seating distance as well.
If you want "Big" and that means crowding the ceiling or walls, then you "absewlutelee" must consider these two things:
A. Mount the PJ at the closest possible Throw to achieve the desired diagonal screen size.
B.Use the darkest possible Screen Paint that will still deliver enough gain, and maintain quality whites and vibrant colors.
Even if you have 10' ceilings, and the side walls are 5' away from the edges of the screen, reflected light will still be an issue with light yellow walls and a white ceiling. So a Dark Gray screen it must be.
With that determined, the only real choice is as to if you want to use a basic Gray with just a few enhancements that offset the attenuation and Gray introduces, or a truly advanced Paint mix that assures you of optimal performance. Once we determine that, we can get into the spraying aspects.