Bscfrank914 your idea - as desirable as it is - is going to require you to scrap the TB seats and replace them with with something that was originally designed to be cooled. Have you considered 1) Your seats move. PVC or fiberglass duct work with some sort of flexible joint/ connector in the confined space under and next to the front seats is going to be tough to do. 2) Any channels cut into the seat foam will instantly create low spots or soft spots into which your posterior will sink. 3) No auto upholstery shop is goint to punch hundreds of tiny holes in your seat covers. If you need perforated covers they will remove the section(s) you want holes in and sew in new fabric that already is perforated.
I have been wrong before and I have not examined the Seat Comfort Systems products but if you want most of the benefits of cooled seats with a minimium of fuss, time, and custom fab work keep your electric heaters and just switch to
cloth OEM seat covers. They are warmer in the winter and much cooler than leather in the summer.