Having to constantly switch between build mode and dismantle mode gets to be quite frustrating and tedious especially when placing things down in the wrong place, having to switch over to dismantle mode then switch back to build mode to continue building.
So why not just combine both of them into one. When you press "F" key for the construction tool, it will appear on the screen but won't do anything until you select a item from the build menu ("Q" key) or from the build WHEEL (press "F" key and held down) to choose from pre-selected items, basically your hotkeys selections. The center of the build wheel is where you will clear your selection, so you don't end up with a hologram floating in front of you all the time when you're in build mode.
Ok, so when you want to dismantle, you'll press and hold the RMB (switching to dismantle mode) then use the LMB to dismantle whatever you want. Once you're done, simply release the RMB to return back to build mode.
Once you finish building, press "F" key to exit build mode.
If you have anything to add please do so, I'm not sure if I've missed anything but I'm thinking it would be better than it is now.