Different Infill density for extruder 1 and extruder 2 on K8400 2

I don’t know if I post at good place and my ask is for the developper.
I make lot of 3D printing with 2 extruders and soluble filament for support. I use essentially cura engine and loose lot of time because the infill density for the support is the same that the piece. It would be great to get the possibility to have different infill density between both extruders in order to choose a smaller infill for the support material.
Would be also nice to be able to have have the possibility to determine a bigger infill density between a layer x and a layer y. Cura engine is my favorite slicer and give me better results that others but damage for these missing options. Others options as temperature of extruder and bed for first layer would be nice also but the most important for me is the infill density. May be in futures updates.

Thank you,