In an attempt to deal with sweaty back issues I recently bought a Ventisit http://www.ventisit.nl/en/ for the Sofrider. This is a distinct improvement in terms of ventilation on the (albeit very comfortable) seats that comes supplied with the bike. Still, it is not perfect and I have been wondering whether punching a series of holes in the seat back will assist with airflow, and with it the evaporation of sweat. Working on the theory that the area of low pressure behind me as I pedal along will cause there to be sucked in through the side of the seat pad and out through the holes at the back. Does anyone have any experience of this? My principal concern is not to adversely affect the strength/structural integrity of the seat back. Any suggestions regarding the spacing and pattern of holes that could be used. Also the diameter. I had been thinking of 20 mm and using a Q-Max round hole cutter to punch the necessary holes.