Which wand for Morch DP-6

Greetings All
I have a Morch DP-6 with a ZYX 3 Airy sliver base.
I have been using the Red Dot wand with the cartridge.
The cartridge has worked very well in this wand except that when it plays a very deep note I get distortion. The one LP that the cartridge has never tracked properly is the very low bass note from Ray Browns LP "Soular Energy"
I sent the cartridge to Soundsmith to have it evaluated (the cartridge is over 4 year old and lots of time on it)
Peter at Soundsmith said that it is worn evenly, but is 70% worn out. He recommend that I replace the Styles only with his best diamond.

My question
Am I using the wrong wand with this cartridge?
The Red Dot Morch arm tube is for a 6 gram cartridge. The ZYX 3 is a 5 gram cartridge, so you should be fine. I think it is better to be a little on the plus side, than on the lower side with the tubes. The Green tube is a 4 gram tube and the Yellow is a 8 gram tube. I would use the Red one, if it was me.

What VTF are you using? The Airy 3 recommends a 1.7 to 2.5 range. I would track at the higher end of that range.
Blu-tack a nickel on the top of the headshell and re-set your tracking force. Tell us if this results in an improvement which I expect to be the case. A nickel, btw weighs right around 5 g.

Thom @ Galibier
Mofi et al, Don't those designations for the Moerch arm wands (in grams) refer to the tonearm effective mass, rather than to the weight of the cartridge that is to be used with that particular arm wand? It makes a difference which.
I use a 12" blue dot arm tube with my Airy 3 SB. The general consensus is ZYX sound best with a blue arm. When I bought the ZYX I went straight for the blue arm on this advice. I have been so happy with this combination that I never felt a need to try my 9" red dot arm. (I have 12" blue and 9" red arms.)
I was mistaken about the arm tubes as Lewm stated. It's actually a combination of the cartridge weight and the arm tube weight that gives a fundamental resonance in the 11-12Hz range.

The BLUE tube is the one that should be used. The link below has a chart of cartridges/arm tubes. Clink on Tonearm...Instructions, then click on Cartridge tonearm combination list.

Sorry for the confusion!