If you want to make the percentage of infill visible these pieces will help. Print each piece with the amount of infill corresponding to the number on them and cancel the print when it gets to 70%. What you will end up with is a "test Piece" that shows the infill and the percentage. Choose any color and filament type you want. The pieces in the image were printed on an Ultimaker (sliced with Cura) with transparent 3mm PLA. To make the number more visible I just used a blue permanent marker.