I like to check their eyes in a dark room with a small-beam bright flashlight (shine from the side across the arc of their eyes)- you should see some cloudiness if in shed.
You mentioned the texture difference of their skin when holding- with a little practice, you'll notice the VISIBLE difference in the appearance of their skin folds, especially on their neck, when in shed. It's hard to explain, but look for it anyway.
Sometimes you can see a bit of a double-edge on their scutes (large ventral "belly" scales) too.
All of my suggestions apply to any color snakes, not just albinos, but it's definitely more of a challenge with albino snakes.
Added moisture (serving wet prey) can help a snake in shed, but no way to say whether it will always be "enough". If only?If you feed, ya takes your chances, lol.