When installing the Aluminum Hovr in plaster & lath walls, you have to do the same thing as with a tile or concrete wall. The female bracket’s bottom edge has to be flush with the wood or shelf. If installed traditionally without adjusting the installation method (meaning the female bottom sticks out by a 1/32") it will break the plaster.
What this means is that the male bracket has to be very straight, otherwise the two cannot connect correctly and you will have issues. This is difficult, since lathe walls are notoriously uneven. So what do we do? To attach the male bracket, our product designer suggests using small screws - as many as possible - in the top and bottom dyeline, like a zipper altering.
Note that the holding strength will be quite a bit less on lath, since your shelf will be attached to 1 section of wood rather than a whole wall in a more standard installation, resulting in much less effective distribution of weight.
If the lath wall is the old style (very thin wood strips), it is quasi-impossible to achieve a proper installation. The same is true if the lath is checkered. Below is a lath wall sample that can work. It is the more modern way these walls are done and the best option for making a Hovr install on this surface.