I can't find the answer, JMW 9 tone arm cartridge

I have the Scout with the std. JMW Tone Arm and I want to try a Denon 103R or the Shelter 501. Right now I have the Dynavector DV10X5. ( High out put and I want the Low out put MC.
How do I determine if I need a head shell weight and if so how much? I look at specs and do not understand all that I am reading. Are all Denon 103R shipped from Japan direct?
This is my first attempt in changing a cartridge so I have decided between these 2 and any input would be appreciated.
Also if a head shell weight is needed where do you buy them ?
VPI sells a 3gm weight. All of their retailers (elusive, musicdirect, etc) probably have them too. They're $15. You probably want it for the Shelter. Not sure about the Denon
Hi Dave, we have the weights in stock
I think you'd want the weight with lower compliance cartridges. When I owned the Shelter and used it in the Wilson Benesch arm it worked well without the weight.

I'd go with a Benz-Micro Ace low output MC cartridge over either of your mentioned candidates. It's more musical than the Shelter, and more detailed than the Denon, in my experience.
Your question is best served by VPI. Also, be aware, that low output carts may theoretically sound better than the higher output models because of a smaller coil, however, your preamp MUST be able to handle the lower output. Check with the cartridge AND preamp manufacturers for their recommendation, and it may not be the low output for the best sound.....
Sorry, no time for a step-by-step, but go to the Cartridge Database, find your tonearm and do a cartridge resonance evaluator table for it. Find the compliance and mass for your cartridge then use the table to determine if it is a good fit for the arm. If the cartridge mass is too light, using a weight may bring it within the prefered range.