Southside "Years" ago single length clubs were a big deal for a short period of time. Did not last long or really improve anyone's game. I tried a few irons the same length because the concept made sense to me at the time. I believe I had the 6 iron on down to the wedges all the same length.
Not all "Single Length" sets are the same. I have played 3 sets of different brands of SL irons. I currently have a set of Wishon Sterling SL's in the bag and they have improved my game substantially. I think what has helped me using the the SL concept is getting the heads to an 8 iron weight. The others I tried at at 6 and 7 iron length were not as successful. And you don't have to change your swing or make any adjustments. My 8 ron has always been my favorite iron. Now I have a bag full of favorite irons.
I think Bryson is an example of how SL can work but I think his swing is a bad example for the average bear who wants to try it.