Ryan – I have a Patagonia Specter (L) pullover. I tested it with the MTI Livery (ML) PFD today. For both warm weather and cold weather modes, I added two wide rubber bands (previously held broccoli together) to closely seal the Specter wrists from paddle drip.
For warm weather, the Specter can be worn on the inside of the PFD and the neck vented. The top strap of the PFD can be worn fairly loose to further facilitate convection cooling. The Specter's kangaroo pocket, for safety gear, is still easily accessible. It lines up even with the bottom of the PFD and negates the requirement for a pocket on the PFD.
For cold weather, the Specter easily fits over the PFD. This mode adds considerable warmth by creating an additional layer of dead air space and makes the most of the insulating qualities of the PFD. This mode adds about as much warmth as a fleece sweater without the issues of having this layer wet when you need it after paddling. Obviously the kangaroo pocket is accessible in this mode also.
I haven't tried this yet but, using an inverted partially deflated packraft with the PFD and pack under it for insulation should eliminate the requirement to carry an insulation pad.



