As far as consistent performance goes I have to bite my tongue. The following table shows the typical specifications for a conventional set of irons (varies between brands as there are no specification standards in the golf industry):

Iron	Head wght.	Length	Lie	Loft	Bounce	Offset	Flex
3	240 gms	39.0”	60.5º	21º	2º	.220”	Weak
4	247 gms	38.5”	61.0º	24º	2º	.200”	Weak
5	254 gms	38.0”	61.5º	27º	3º	.180”	Wk/Reg
6	261 gms	37.5”	62.0º	31º	3º	.160”	Regular
7	268 gms	37.0”	62.5º	35º	3º	.140”	Regular
8	276 gms	36.5”	63.0º	39º	4º	.120”	Reg/Stiff
9	284 gms	36.0”	64.0º	43º	4º	.110”	Stiff
PW	292 gms	35.5”	65.0º	47º	6º	.100”	Stiff
GW	292 gms	35.5”	65.0º	51º	6º	.100”	Stiff/X-stiff
SW	298 gms	35.0”	65.0º	55º	12º	.100”	X-stiff
LW	294 gms	35.0”	65.0º	60º	8º	.100”	X-stiff

How this equates to consistency I do not know. I would like to point out something from the above table that most golfers do not realize and that has to do with the varying shaft flexes within a set of conventional irons. Regardless of what the shaft bands state, every one of the irons in a conventional set has a different shaft flex that gets progressively stiffer from the #3 iron to the wedges. To prove this to yourself simply hold the clubhead of a conventional #3 iron in one hand with the grip in the other hand and bend it - then do the same thing with the PW from the same set and you will see what I mean.

Another thing that most golfers do not realize is that in a conventional set of irons the clubhead weight progressively increases from the #3 iron through the wedges. This results in a greater amount of mass impacting the golf ball with the wedges than the low lofted irons. Wouldn't you want the higher impact mass associated with the iron that is designed to produce the most distance? Enhanced and consistent performance? - Go figure.

The specifications for a set of 1 Irons are shown below. With the exception of the bounce angle on our SW the only difference between irons is the exact 4º loft angle progression from the #3 iron through the wedges. The reason for the additional 3º of bounce angle on the SW is to enhance play from a soft bunker. You may note that the bounce angle of a typical conventional SW varies from 10º to 14º. Bounce angles this high produce a clunky shot out of the sand and make playing shots from a close cut fairway virtually impossible. What is sad is that most golfers will continually blade shots out of the fairway with a conventional SW without ever even understanding why. Our 1 Iron SW was designed for highly effective sand play as well as fairway play, and an interesting point is that part of my design testing for our SW involved hitting balls off of a cement driveway (no skulled shots with our SW).

Iron	Head wght.	Length	Lie	Loft	Bounce	Offset	Flex
3	275 gms	Same	63.5º	19º	3º	.125”	Same
4				23º
5				27º
6				31º
7				35º
8				39º
9				43º
PW				47º
GW				51º
SW				55º	6º
LW				59º	3º

At the end of the day you just have to leave all of the marketing hype about custom fitting and conventional golf club design behind and simply rely on plain old common sense.