This looks very promising, than you for taking the time to do this 
Although I'd suggest adding some kind of visible scale on the opacity slider, either notches along the slide or ideally an actual numerical value at the side so the user can keep opacity levels consistent across different designs
Although I'd suggest adding some kind of visible scale on the opacity slider, either notches along the slide or ideally an actual numerical value at the side so the user can keep opacity levels consistent across different designs