This question is pretty basic. I already have a patio made from Unilock pavers, done professionally. It is made from 2 sizes of Canterbury pavers, a rectangle and a square. The whole patio is edged in contrasting Hollandstone.

I now want to create matching stepping stones leading from the patio through an adjacent garden bed. I also want to edge the bed with matching Hollandstone pavers. I am planning to do this work myself. I will not have any help (husband wants no part of it. Crazy garden projects are just not his thing).

For the stepping stones individual pavers would be too small. So I decided to put 2 rectangles and 2 squares together to make up each unit, which would be about 10 inches square. Since I don't want them to sink or tilt, I decided to do this the right way and dig out some topsoil and lay paver base of finely crushed stone. The landscape supplier had stone made for this purpose.

The question is, how much? Considering that the stepping stone units will not be anchored to anything, what depth of crushed stone will be suitable? I would have to dig down through about 8 inches of topsoil to reach clay. I sure hope I don't have to do that.

Ditto for the hollandstone edging. There the plan is to make a mowing edge for the garden bed. They will be laid with the long edge perpendicular to the edge of the bed, which matches how the trim runs on the patio. So it needs to be low enough to mow over and not be scalped by the lawn mower.

Can anyone point me toward a site with some guidelines for what I want to do? The book I leafed through at the library was more directed toward big projects.
Thanks!