GameplayAbilities and you

So my gameplay effect now plays well by providing a proper target. Since I’m on a dedicated server scenario the target always null on aserver without target no execution of gameplay effect. With the target replicated to the server (actor below mouse cursor if some might ask why rep from cleint to server) and used in the call to apply gameplayeffect to target everything was fine.

Now I have a gameplay related question I am not sure how to solve this, and have not found this in the wiki covered. How or where do I make a functionality like a% to hit chance roll which only the triggers the abilities. I tried the % roll to be on the authoritive side and replicate to the client. I even placed net sync nodes to be sure I have the avlue set, but client and server used different rolls to decide after the sync. So I am not sure the documentation covers any such case. To me it seems it is more relying on everything doing the same fixed calculations.

Anybody an idea how to introduce authoritive random values like skill rolls with gameplay abilities?