I guess this is not really what you have in mind, but I'll let you know anyway. :-) When I want multiple plants of a kind using SolidGrowth (using Vue d'Esprit 4), I go to the selection box for the first and place it. Afterwards, I shift my top view editor window so that the location for the next plant is in its middle and then left click the plant icon. I'm not sure whether there is a setting to control this, but in my setup, the new object will appear in the middle of the top view window. Indeed, you have to go to the icon each time, but for me, I think, this is the quickest way of positioning a variety of plants precisely. Clicking the plant icon is in my experience much less time consuming than correctly adjusting the height of each plant (lift and drop or drag manually) because they appear rarely at the actual terrain surface and dropping groups of plants will often leave some in midair over a wavy terrain when the first touch the ground. For really many plants, I use scatter / replicate or start with a group of plants that I copy / scale / rotate all over the place.