Stream of Consciousness and base chances of encounters + Synthesis

Hey,

I'm not sure whether it's worth or not to pick the keystone, so:

1) I guess the wording specifically means the "+X% chance to find said mechanic" doesn't count as base chance ?

2) Do we know how much is this base chance ? Does it depend on the encounter ? If so, I'm after the numbers for Expedition, Harvest or Harbinger (but there is a map mission for this one so I guess I could force it anyway).

Untelated question regarding Synthesised maps: now that the nodes for synthesised items to drop, are they trash, or do monsters drop some synth bases for some reason ?

Thanks !

Unless things changed, the base chance is 8%.

OK, good to know ! Not sure investing in harvest is still worth it but I'll give it a shot.