Dynavector/ Thorens compatibility

Hello all,
Newbie question.I have just installed a new cartridge ( Dynavector 20X) on my Thorens TD 850 ( with a Thorens 300 arm;I believe an OEM Rega RB 300).When setting the tracking weight( aiming for 2g), I have had to move the counterweight well back down the arm , to the extent that it sits partly off the back of the arm.Have I made a dumb mistake or is this cartridge too light for this arm?
Many thanks for any help,
Sounds like the cartridge is actually heavy enough to warrant the use of a counterweight heavier than your current one to balance the arm. I hope I interpreted your description correctly.
No mistake. Worst case you'll need to get a lighter counterweight. For my Dynavector MkII (karat) to work with my JMW9 tonearm, I had to buy the heavier counter weight or was it lighter?

No big deal though.