This is an update to report the results of PIA abatements.
1. I got a new “type D” tractor seat from ZRE. I had several conversations with Chad at ZRE regarding the dimensions of the seat frame. I expected to receive the seat with separated mounting tubes and instructions for mounting the tubes to the bottom of the seat. When I opened the box I was surprised the tubes were already mounted and the seat fit perfectly on the Advantage. I paddled for a couple hours yesterday with no trace of the PIA issue. The ZRE seat is a little taller in back than the Wenonah seat and I felt much more locked in. The seat is narrower, and I may add padding at some point.
2. I discovered two makers of nylon pants that don’t have the crossing seams in the back: Patagonia and RailRiders. The water has been too cold to paddle without my drysuit, so I haven’t yet tried just the pants on the Wenonah seat, but under the drysuit neither pant produced PIA. Further testing of just the pants needs to wait for warmer waters.