Do Cura's self-crossing infill patterns account for excess material from self-crossing?
With most filaments you don't need to do anything special to account for overfill caused by these crossing points. When the nozzle extrudes the second direction, it pushes the lines laid by the first direction out of the way. The same happens when the third direction crosses the first two. There's a blob, but it's a blob within the plane of the layer, so it shouldn't stick up out of the layer and upset subsequent layers. There are two complications which can occur though:


When filling each direction, it's usual to keep extruding when moving from one line to the next (not a travel move), which results in getting an extra half perimeter around your infill. This is fine for a single raster pattern, and for box infill, but with triangle, hexagram, or similar, you'd get three half-perimeters (one for each direction). The slicer needs to offset the third direction so that those extra perimeters don't overlap. I don't know how Cura handles this; it's possible that's the source of the dimensional problems you're seeing.
With abrasive filaments, or those that don't stretch (such as carbon fibre or metal fill filament), the "pushing the existing lines out of the way" doesn't really work. You just end up wearing down the outside of the nozzle and getting the kind of blobs you're afraid of, sticking up into the next layer. It's just best to avoid infill with crossings (box, triangle, hexagram, etc.) on such filaments.