well, the head is still together.
So far i removed below.

intake manifold, exhaust manifolds, valve cover, thermostat housing, radiator and timing cover oh, the fan as well but viscous clutch still attached with stripped bolt.

Now i'm trying to remove the head and following this instruction below. i've done up to figure 23 which i moved the air pump to side and I guess i could turn the engine to TDC before i remove the tensioner but this is where i get stuck....

taeandji, the viscous clutch has no effect on rotating the crankshaft CW (when viewed from the front) with a 27mm socket and breaker bar.

It seems to me that you are getting in over your head attempting to replace the head gasket on your own. Things will only get more complicated/difficult as you proceed, especially if you lack the proper tools.

Thanks for your input but I had another thread going with different topic but ended up with the same question as i moved on from a stripped bolt on the viscous fan clutch to TDC issue.

Long story to short, talk to one of local indy MB shops and they were all concerned with turning engine more and recommended to go ahead to remove the head and deal with timing later. So i removed the head and found out a few valves from cylinder #2 & 3 were sticking out and caused issue i was having to set it to TDC. Luckily, i didn't force to turn otherwise, it would have more damage to valves and the head is at a machine shop for inspection and testing.

I always pull them apart at where ever and only worry about timing the engine going back together.

Yep, but the issue is our guy hits a hard stop when turning. I see him getting the head rebuilt then finding out the engine has lower end problems.

Turning to TDC is good practice for a person that hasn't worked on a particular engine before as it lets them see where the marks are supposed to be.

Some engines ( a few OHC diesels ) are not set up with a piston at TDC, this eliminates the possibility of crashing a valve during setup.

Mercedes startekinfo.com has the factory service instructions online for free. You may want to look at these.

Thanks