User-defined Snap amounts for Move, Rotate and Scale tools

The Move, Rotate and Scale tools (in the toolbar) don't have too many Tool Options at the moment. These tools could be given an additional tool options that let the user enable custom snap (that limits thet tool's movement, rotation or scale increments, and define the exact amount of snapping.

The exact implementation could be done in a few different ways. For example, should custom snap options override the general, already existing snap options, or should those snap options override the custom snap?

There are other existing requests for implementing customizable snap amount for the existing snap tool. For example, the suggestion here blender.community/c/rightclickselect/xZbbbc/ . This suggestion doesn't replace the need / use for those, but might be easier for new users or in different use cases. If user-defined snapping is considered, it'd be better to look at the various suggestions and see which ones work the best.

Mock-up screenshot below.