Crafting on iOS / iPad

This is a frustrating one when working with a classroom full of students. When crafting, it is almost impossible to select a small quantity of blocks from the hot bar and move them into crafting table. I can move all 64 blocks, or I can tap/hold which shows a progress bar but there is no precision or method in this. For example, if I am using the Lab Bench or the Material Reducer to create a a recipe that require 1 or 2 blocks of a material, it is next to impossible and thus the lesson breaks down.

There needs to be a way to be specific about the number of blocks you lift on devices that use touch controls. I can imagine there isn't straightforward solution for this but I can tell you from using this in a classroom full of kids -- that it doesn't work. We have the same issue with another lesson we do, where the students craft their own fireworks and have to follow a precise recipe.....it can't be done, unless I am overlooking something.

My suggestion would be, that tapping on the hot bar will select '1' block long press, double tap will select all 64 and long press will increment upwards to 64 with progress bar (or whatever the max quantity is in the hot bar). 

I'm sure this will cause issues elsewhere in the game so perhaps its something that can be toggled on/off in Touch settings 'Precision Selection for Crafting'?