Do you have a guess as to what the overall effect ketosis has on weight loss?

I don't have proper data, just anecdata -- suitable for WAGs (wild-ass guesses) but not much more.

the efficiency of my diet

What do you mean by that?

Besides, being in long-term ketosis tends to lead to many consequences unconnected with weight loss or gain. See e.g. here for some discussion. Anecdotally many people who's been on VLC diets for a year or so tend to develop problems that go away when they add a bit of glucose (=carbs) to their intake.