I agree with
@Ajmassa -- it's winemaker's taste AND blending trials can be difficult to judge.
Look at the back label of red Bordeaux and other red blends. In some cases there will be as little as 3% of one varietal. The winemaker believes that addition makes the wine better. Maybe it does, but I'm not going to claim my palate is good enough to detect the difference between 3% and 5%. Or maybe the winemaker is fooling him or herself. Or blowing smoke. I have no idea either way.
Also keep in mind that these folks have hundreds, maybe thousands of 60 gallon barrels to play with. We amateurs do not have that luxury, and the amount of wine we make is a strict limit on both blending
and taste testing.
Go with a simple trial, 5 wines:
100% PS
75% PS / 25% CF
50% PS / 50% CF
25% PS / 75% CF
100% CF
You want at least one other person to taste with you, if you can. Rank the wines 1 (favorite) to 5 (least favorite). Make the blend that is the most favorite, and use the remainder as the 2nd blend. Keep in mind that you may choose to go with no blending.
Keep in mind that there are probably going to be no losers -- all 5 will be good. Just a question of what you like he best.
If you want to get creative, do a double-blind tasting -- you randomly label the wines 1 to 5, secretly recording which is which. Then someone else randomly re-labels them A to E, recording which is which. Now no one knows which wine is which.
Taste as above, ranking the wines from 1 (favorite) to 5 (least favorite). Reveal the notes to determine which is which.