Yo! Final renders for the Shack that I just completed.
I designed the house so that roughly half of it would use tiling textures.
Since a lot of surface area used the tiling textures, I didn't want the bulk of my mesh to look flat. To sort of get around this (since the default ambient occlusion in Marmoset looked bad), I made ambient occlusions for everything. It is a bit more difficult to use ambient occlusions for tiling textures, since most of the time the UVs aren't contained within the unwrap box.
Example: Tree unwrap for my the Shack
What you can do though, is make another, separate unwrap for your object in the second UV channel.
After making that second unwrap, you would then bake your ambient occlusion like you normally would, with one change. In the render settings (for Max) under 'Mapping Coordinates' there is a roll-out that, by default, it set to Channel:1. Just change that to Channel:2 and it will bake the ambient occlusion according to that second unwrap.
When exporting (and rendering in Marmoset) is it important that you export as FBX and not OBJ since OBJ does not have the capability to save more than one map channel.
So - what difference did using an ambient occlusion actually make?
Quite a big one in my opinion. Really makes the scene look more dynamic. Now, i'm not entirely sure how much memory this saves, if at all, since it sort of countermands the reason most people use tiling textures. This does come in hand, though, with these little rendered scenes.