I experimented with card wards in the .45, .40 and the .69. Only the .69 did not care they were there. I used them to prevent power contamination by the oil or grease when hunting, but found through testing that the 'wad' was not necessary. In the .45 and .40, the use of a simple card wad doubled group size. I did not test fiber wads. Perhaps a bit more powder would have given me back the accuracy I lost using the cards, I do not know, as I did not test that far.
With the load combinations I use, there is no cause nor reason to use a wad as there NEVER is a fouling problem - EVER. If you have a fouling problem when not using a wad, your patch is too thin. Use of a thicker, stronger patch that eliminates ALL fouling buildup, will give you the best accuracy from your rifle as well. Use of a substandard patch and a wad will not shoot as well as with gun will with the use of a proper patch alone.
Using a load 'protection' wad to reduce fouling, is finding a fix a problem that should not be there to start with.
There will be no pressure problem generated in using the wad if your barrel is of decent quality and of proper wall thickness.