Please give us the setting for the Infilled line multiplier for using less plastic with greater strength

with a double line infilled you can make a 10% infill as strong as a 25% infill
Also please add a layer change infill amount settings to the slicer preview, so say at layer 5 we want it to be 90% infilled but layer 4 and 6 we want it to be 50 like the rest of the model, to do that we need to change it at layer 5 then change it back on layer 6 but we don't have this an an option

Reason:
https://www.youtube.com/watch?v=yskFuq8VjtA
He talks about it at marker 2:27