I emailed the folks at Red River inquiring about their paper and the S800. Here is a portion of their response. (Note the recommended settings).
From Red River:
"In general, I like the Photo Paper Pro setting on our heavier papers. I
would only use the High Res Paper setting on lighter weight sheets and
practice grade stocks. In the Canon advanced print manager, we recommend
you move the quality bar all the way to the "fine" setting on the right.
This will slow your printer some, but the quality gain is significant.
Finally, you may see the Canon make quite saturated images. If this is the
case (try this also even if you don't think they are saturated), go to the
saturation bar in the advanced manager and reduce to about -10. This made
an improvement on our test prints.
Our UltraPro Gloss, Satin and Polar Gloss are similar to Canon Photo Paper
Pro and Ultima papers. Although we profess to offering higher grade sheets
than these products! The UltraPro Satin is quite popular because of its
slightly bumpy E-surface like traditional portrait papers.
I strongly recommend the Customer's choice kit as a good starter."
From Red River:
"In general, I like the Photo Paper Pro setting on our heavier papers. I
would only use the High Res Paper setting on lighter weight sheets and
practice grade stocks. In the Canon advanced print manager, we recommend
you move the quality bar all the way to the "fine" setting on the right.
This will slow your printer some, but the quality gain is significant.
Finally, you may see the Canon make quite saturated images. If this is the
case (try this also even if you don't think they are saturated), go to the
saturation bar in the advanced manager and reduce to about -10. This made
an improvement on our test prints.
Our UltraPro Gloss, Satin and Polar Gloss are similar to Canon Photo Paper
Pro and Ultima papers. Although we profess to offering higher grade sheets
than these products! The UltraPro Satin is quite popular because of its
slightly bumpy E-surface like traditional portrait papers.
I strongly recommend the Customer's choice kit as a good starter."