Snapping in orthographic views is zoom dependent (if you keep zooming in you will snap to increments of 0.1, 0.01, 0.001, etc).
Snapping in tumbled views depends on viewport grid scale setting:
If you don’t want to keep typing different scales you could create shortcuts to change grid scale like in some level editors:
3D View → 3D View (Global)
-
wm.context_scale_float
space_data.overlay.grid_scale
10.0
=
wm.context_scale_float
space_data.overlay.grid_scale
0.1
That way you could increase / decrease size of viewport grid with - / + buttons.