Melm, when you learn something about tonearm design, let me know. Then we might be able to have a productive discussion.
FYI, I HAVE used a DL103 on many different tonearms, but only an idiot would even try one on a JMW. If you think that this is not a problem, maybe you should try talking to Harry about it. Do you think Harry would introduce a set of optional outriggers to handle cartridges of low compliance, if they weren't needed? He says that the outriggers are needed for even cartridges of 9cu like the Shelter and Koetsu. He doesn't even try to mention the 103 at 5cu.
My only comment to your(and Art's) use of a 103 on a JMW is, that you don't know what a 103 sounds like when it is in a proper arm for it, or you would not have made statements as you did. Just because it makes sound doesn't mean it is good in the arm. It is people like you, who will throw any cartridge into any arm, and hope it sounds right, that makes getting into analog needlessly difficult and problematic for beginners. I think the JMW is a fine arm with the right cartridges. Unfortunately for you and Art, the 103 is NOT the right cartridge.
The JMW is neither the correct mass, nor stable enough for a 103, and that is a plain fact.
I see this very commonly, especially with JMW users. They think that just because they bought an expensive nice arm, that it can be used "willy-nilly" with any cartridge, without any concern for matching. Well, I'm sorry, but that is not the way it works.
Like I said, try spending about 30 years learning about this subject, and maybe we can talk then.