Seems like Edwood had asked Daniel Winkler if he could make a shorter version, then started selling them from the website. If I remember correctly, Ed wanted something that would wear better on a chest rig or under the arm(concealed).
I had to make the same decision, and I chose the original length. I'm 6' tall, and I can still sit down with mine riding on a molle vest(RnD attached to my left peck area). I thought that the original version had been designed, and tested for over a year, that was the length that was agreed on by the designers. Without having both in hand, it is hard to know which one may be for you. Yet, if concealment or wearing it on your chest is not a concern, get the full length. They aren't very big, compared to lots of other hawks, with longer hafts.
The weight and size is perfect IMO, of the original size. I know that JK makes several versions, and that maybe having different length hawks is of some appeal. I have 3 hawks that are about the same length, 13". The Winkler, the SOG Fasthawk, and the GG&G Battlehawk. I train with the GG&G for strength and endurance, and the Fasthawk because it's a beater, and being the same length, I always know where the edge is. I have longer hawks as well, and I also have a good feel for them.
Maybe you could just pick up any hawk and have a feel for it pretty fast. I just like the repetition of training with the same length hawks, to help keep that particular intuition and edge awarness.
I would love to get a JK Cassam, it's about the same length as my RnD, but would not bother me. If money wasn't an issue, I would also get a shorter RnD, but it would be less of a priority for me. I don't think there is much weight difference between the two different Winkler lengths, maybe an ounce or two. The Cassam weights about 33oz vs. the Full size Winkler RnD's 24oz.
Hope that helps in some way.
