Well I can tell you how I have been doing it with Musette as she is now on .4u. And that is lots of practice with colored water until I could consistantly get 5 drops out of .5u of insulin. Then I just fill to the .5u make and squeeze out one drop that gives me the .4u and inject that into Musette. I believe when you get down to .1u you would do the same, just fill to .5u and squeeze out 4 drops to get you to the .1u and then inject that. The other way would be to squeeze out those drops until you get down to where you think that 1 drop is and then form it on the needle and suck it back in to the needle before injecting.
Hopefully someone that is actually gotten down this low will be able to answer you better but at least this is how I'm getting to .4u with Musette.
Mel, Maxwell, Musette & The Fur Gang