F.I.T is another good one, I have the +5 and really like it, but it's not strong enough on the LX100. For the F.I.T +8, it's 43mm at the back and require a stop up ring to 67mm? If that's the case there might be issue on the LX100 with the diopter flip holder.
Here is a good review of the F.I.T +5 and +8 by Alex Mustard:
Yes I agree I have the +8 one but it is the 67mm version not the 43mm. I think you can order either way.