There is no adjustment, other than bleeding the fluid - it's all in the service manual, chapter 6.

Now, as to your complaint...
My Graphite was kinda sluggish or 'catchy' like that. Based on advice from others here, I changed the transmission fluid at around 55,000 miles - took a bit less than two quarts of Mobile 1 5W20.
It was better, but still a bit 'catchy', until I got close to 100,000 miles - honestly, it shifted smooth then. What our transmissions really need - is about 90,000 miles on them! (My current SE has new oil and 57,000 miles on it - not bad but not as nice as the Graphite at 90,000.)

With those miles (and YEARS) yours is way overdue.

(Yes, I know there is a specific Mercedes-approved manual transmission oil, but if some can run regular gas, I can run Mobile 1. Besides, boiilerupXfire and JohnMoorhead both used Mobile 1, and they are more 'gearhead' than I will ever be.)