After getting everything sorted, I burned through nearly all my sample pack on one black and white sample image and a couple of color samples. I am a hobbyist and do not have the same critical eye when evaluating prints, compared to others that frequent this forum. I was stunned at the difference in prints between the prints I made on the p600 with Canson Photographique and the p600 with Baryta and Plantine. The black and white prints revealed more subtle details in the shadows and midtones, exactly as i hoped. The Plantine paper was the winner for me and i loved the feel of the paper as a bonus. I did not see quite as much difference on the color prints, but I don't think i had selected an image that would play to the paper strengths. Still i am switching from the Signature Worthy papers and Canson and moving to these legacy papers.
On the Matte papers, the Fibre was amazing on the blacks when i printed an early morning sunrise picture with lots of range (bright sun to dark areas of the incoming ocean waves). So that will be good if i want a rag feel paper for a portfolio. The etching was interesting but i don't think i have a good image yet that would take advantage of this.
If a rank amateur can see this kind of difference, skilled amateur and professionals should be delighted and the cost of the paper is well worth it.
Finally, the Back to the Print videos were terrific to watch. Kudos to Kevin, Jeff, Dan-o, Mark and Chris on the excellent information and quality video.