I know this is a crazy old topic, but since I’m spending my days dealing with this recently, I thought I’d share what I’m doing. I made a material that uses a noise map and an alpha threshold to help see where alpha values are. This works well enough if I’m using the alpha for actual transparency, but alternatively, you could always split the RGB and output Alpha instead of one of the other channels. This would let you see smooth gradients more obviously too.
