You've been reading too many Trapshooters.com threads. They are both decent wads. I use the Remington in Remington Hulls and the Winchester in Winchesters, generally. As for plastic fouling, it's not as prevalent as some might believe. I get a little bit with almost every wad I use. It depends on the barrel, the load, and how often I clean the gun. As for patterns, it can vary depending on the load and the gun. I don't put as much testing into patterns anymore. If they are average, I don't lose any sleep over it. I don't think the targets really know the difference.
I used the WAA12 wad for many years, then I was forced to make the switch to Remington. Many of the WAA12 wads petals were folded inward (about 23% of the bag). This isnt a problem on a MEC as you place the wad up into the tube as you pull the handle< but I load on a ponsness press and you place the wad in a holder. The folded petals would get caught by the shot tube and fill the sppace that was to be for the shot, spilling it over the case mouth. Plus I was concerned about bare lead speeding its way down the barrel and getting deformed. wasted time and money messing around with them. Very surprised this issue has not been adressed by Winchester as I am sure they are losing business becouse of it.
Regarding folded wad fingers causing reloading issues, a friend told me to place them into a laundry bag and throw them into the dryer for a short time and that they would return to their original shape. I have not tried it but it may be worth a small experiment.
I don't think you will see a difference in patterns. Excluding some exotic wads, wads don't affect pattern to any material amounts. Chokes affect patterns, shot quality and hardness to a lesser amount. The other factors are trivial by comparison..
At lower FPS.. your statement it pretty accurate..as long as you don't put a unslit wad next to a slit wad.. But once you get to higher speeds.. the strength of the base section starts comming into play.. as well as the design of the floor of the shotcup.. A flat base.. next to a concave base..next to a convex base will give you a measurable difference..
This question asked a very specific question what I have tested.. I found the figure8 wad at 1250 gave me an additional 2% in the inner 20" circle at 35 yards.. It was a repeatable test for me..I'm thinking about 40 patterns of each.. I forget what barrel I was shooting.. but it was for a 27 yard load..so probably .032 or higher.. Shot was probably WEST COAST..the cheap stuff..Which is much of what I have loaded in the last 20 years.. or any of the cheaper shot I could buy at the club when they ordered targets..
Okay PBB - 40 patterns is certainly enough to determine whether you have a statistically significant difference. But is 2% a material difference?
Since you say is was a 27 yard load, I venture that it was 7 1/2 shot. That should have 393 pellets in that load. And most of those will be in the inner 20". Let's say 75% of them. If so that would be 295 pellets in the inner 20". A twp percent difference would be six pellets. Is that a material difference?