Solid infill threshold area

Hello guys.

I am trying to slice a vase. I am running into a few issues.

First problem is the first few bottom layers. They are especially flat and I want to generate gcode that will not make layers that have 100% infill. See picture attached.

Is there a parameter that controls this?

The Slic3r manual says that the "Solid infill threshold area" parameter is for: "Small areas within the model are usually best off being filled completely to provide structural integrity. This will however take more time and material, and can result in parts being unnecessarily solid. Adjust this option to balance these needs." Does this apply to these layers? How does this parameter behave? For example what happens with we increase it and what happens when we decrease it? I have tested out setting it to zero and to 100 and haven't noticed any difference.

Second problem:
I have tested zero top layers. But setting it to zero makes the inner perimeters have no bonding to the external perims; the infills just vanish as if I had set 0 for infill completely. Is this a bug? This happened when infill was set to 10%. At 15% this did not happen.

Third problem:
After increasing the infill to 15% the problem of the disappearing infills was solved but there are still some solid layers being generated on the outter perims of the low layers.

Fourth problem:
I have also tested slicing a solid model so that I just generate perimeters but since the top rim of the vase is angled slic3r generates a cap that bridges the top (effectively closing it).

Any suggestions?

Thanks!

Just an FYI: I was unable to recreate the disappearing infills problem after setting the infill to 10% again.