Leica CRF 1600-B Zero Ranges

[Spurwing]

Good Morning all

I recently acquired a Leica CRF 1600-B.

Awesome unit..super fast...

Here in South Africa we are using the metric system.

I need some help regarding the Zero distances...there is 100m, 200 m and a GEE (most favourable zeroing range)...what does the latter mean...GEE (most favourable zeroing range)??

And then, my rifles both have Nikon scopes on, the one has click =1/4 per MOA on 100m and the other has click =1/8 per MOA at 100meters..

The Leica does not provide for 1/8 clicks, could I simply use the 1/4 setting and x by 2 for my scope with a 1/8 setting?

Regards