Ahh soz, mixing scale velocity with a similar characteristic in houdini. Scale vel just scales the display of velocity rather than the velocities themselves.

100:1 sounds crazy,
Rendering animations at 240 fps is also ott and not practical,
Also remember changing gravity 10 fold might make it feel accurate but thats only the one force and isnt really a practical way to tackle a scale issue.

The reason your slide setup might have broken is that your tolerance was too high, if its what it should be its a value that will tell maya to not bother solving a force if its below a certain strength, so when you working on a 10:1 scale and its not solving its just because maya isn't expecting forces of that size and considers them a waist of calculation and doesn't bother.

TBH the maya rbd solver is a little crap, bullet is really good if you can get your hands on it, really fast and stable.