The resolution was kinda low and it had heavy screentones all over it, so I used a model that upscales to 4x the size while getting rid of the screentones. The results are very impressive (for this specific doujin anyway), so I thought it was worth sharing for anyone who might prefer a cleaner look to the artwork. It looks more like a proper digital release now, at least to me.
I've seen quite a few galleries of this type, so I think it might be okay to post this. This is not intended to replace the original gallery, of course.