The CMC should allow you to shoot something 32 mm wide full frame by itself. The problem is that your LX100 is not a very stellar macro shooter. Adding a + 7 to the CMC should get you to something like 30 mm full frame (not a big improvement). The SAGA +25 will get you by itself to something like 30 mm full frame (a bit more than the CMC). Unfortunately the physics of your camera are the fundamental limitation to shooting something that is 4 mm across.
A lot depends on your focus distance needs. Once you get beyond +15 or so the biggest worries are DOF and can you find the critter. I think the CMC is very well designed (at least for my macro lens) and is quite nice optically. I haven't seen the Saga but always worry about CA with such lenses.