The only need for a drive shower is if you cap off the water intake from the drive and move to a thorugh-hull pick-up like an inboard. The water intake through the drive is what cools it. On plane the upper portion of the outdrive is out of the water and can get warm over time.
Thanks for your replies. My only thought on this is because I'm going to be making a few trips across to France this year (60 miles) about a 4 hr passage, pretty empty going there but obviously making a boozy stop at the supermarket before returning.