It depends on why you are using a coulter in the first place. As Thud describes the 25W x 7/8" wide blade is good at breaking up a tough usually dry crust. This is why they are often used in Texas and the southern great plains.

The 7/8" wide 24 or 25 wave blades are NOT as good at cutting tough cornstalks as a narrower blade with fewer waves. They loosen more soil but then you lose the "guillatine" (sp?) action of cutting against an edge that the blades with fewer waves have. A 25 wave also hairpins more material in the slot rather than cutting it.

If you are looking at a coulter as a means of supplying some loose soil for the rubber tires to close, NEITHER of them do a good job of that. The rear edge of the double disk opener blades at corn depths is about 1-1/4" wide at the top where it exits the soil. In many tough no till soil conditions - as no tilling beans into corn stalks in your original post - you will still have smeared sidewalls unless you use a blade of 1-1/2" or 2" wide as used to be called "Waffle" coulters.

These will often also leave a ditch in some soils that you could lay electric wire in, which is why they are seldom used any more.

We have come to think of planter unit mounted coulters as cutting tools, not soil working tools. A coulter does also significantly increase the life of the double disk opener blades and adjustment in many conditions.

The best cutting coulter I have seen is a "Ripple" blade, also called a plow coulter. Cutting ability is why they are used on plows and have been for many years. Our "Ripple" is only 3/8" wide and has many little ripples out to the edge but those are to keep the blade sharp as it wears and turning - not soil working.

The 3/4" wide, 16" diameter, 13 Wave blade is a fairly good cutting blade which loosens a bit more soil for the vee opener but does NOT usually work loose soil to close nor does it eliminate sidewall compaction in wet heavy soils.  In mud the 3/4" 13 Wave has fewer transverse surfaces to act as paddles than a 7/8" 25 W.

As Thud points out, the 7/8" 25W is a good "crust" blade, but the 3/4" 13W is a better cutting blade. Ripple would be better yet but in your stated conditions above I would go with a 3/4" 13W. I am personally NOT a fan of the 1" wavy blades, they will tend to fracture dry crust better but also tend to lift wet mud.

Here is a link to a series of photos in heavy WI clay that Joe took a couple years ago showing how the 3/4" 13 W blade does nothing to eliminate sidewall smear or produce loose soil to close in heavy wet clay. This series also illustrates why we now think of the coulter just as a cutter, where needed, and take care of the sidewall compaction, etc in the back with the closers.

Here is a link to a photo which illustrates the nature of the waves and nomenclature. We no longer stock the Bubble blade which actually often makes sidewall compaction worse. At best the Bubble blade is a Texas/southern plains clod buster. The 25 wave is now taking its place.

Talking about planter coulters is a bit like trying to discuss race and religion, no matter which you choose, if your wife leaves you right after planting it will be because you had a 13W rather than a 25W. Or vice versa.

Best of Luck this spring!

Jim at Dawn