A quick look for mylar caps on digikey indicates the pin spacing is .2 in so select a ceramic cap from core and with it selected in the sketch in Inspector change the package from 100 mil (.1 in) to 200 mil (.2 inch) and you should be away. Basically you need to match the pcb footprint to the package size of the mylar capacitor you select (if the physical size of the cap is large you may also need to also allow some more room to surrounding components on the pcb assuming you are making a pcb).
Peter