Another way of getting print in place to work well.
is slicer dependant.
both flashprint and simplify3d allow you to adjust the gaps between internal 'walls' - parts.

The beauty of this method is that nothing else changes. So you don't have to fiddle with extrusion percentages or temps etc.

In simplify3d it's at the bottom of the 'Other' page.
Called horizontal size adjustment

In flashprint it's also in the Other section.
Under Dimensional adjustments.
That's actual better than s3d as it included seperate internal and external adjustments.
It's also where flashprint hides the z-axis adjustment. - and I did not realise until just now :-)