My towel is very rarely used for water ingress as I tend not to drive with the hood up anyway
(I have the hood up now as it’s a bit chilly and wet but it’s just to stretch it after a year of it being folded which isn’t really a good thing - note to self - must put the hood up more often through the year in the garage to stop wear marks )
My towel is more used to get rid of water that ends up lying on the tonneau cover or on the storm cover so I can pack it away relatively dry after a shower if it’s been parked
If water gets on the leather as it usually does when I’m driving in the rain then I just keep wiping it off so it doesn’t get soaked