I have done that job
I did the head on our 300TE a few years ago. Unfortunately I did not think to take pictures.
I too struck a problem with the drive for the distributor rotor. Tread very carefully here. The screw is in a deep recess and requires a Torx driver. The problem I had was that someone before me had slightly damaged the screw and the Torx driver would not remain seated in the head of the screw. Fearing further damage, I made up a clamp plate that held the Torx driver bit firmly pressed into the screw head. I was then able to use a spanner (wrench) on the Torx driver bit to apply the surprisingly subtantial torque it needed to loosen it. So much torque that it twisted the Torx driver bit. The next surprise was when my local dealer (and other MB parts suppliers) could not supply a replacement screw. Their part number was for a hex headed screw of a different diameter. I believe the earlier M103s may have had this. The Torx screw from memory was a strange size (possibly M7). My solution in the end was to source a high tensile screw of the correct diameter and length but with a hex head. I then used a thin walled hex socket to fasten the screw. I have added that socket to my collection of special tools. With the hex head I should never have this problem again.
Good luck with the job you have ahead of you. If it helps to reassure you, I don't recall encountering any other problems doing the job. One tip that was suggested to me at the time was to leave the inlet manifold and all the associated injection system in place in the engine bay (attached to the engine block with the steady brace) rather than removing it all as suggested in the shop manual. This saves considerable disassembly and reassembly work. It is not difficult to lift the head off the block and away from the inlet manifold at the same time. On reassembly ensure that the inlet manifold gasket and head gasket remain located on the dowel pins as you position the head back onto the block.
The only other aspect that was new to me was the terrible feeling the head bolts give as you torque them. They are stretch bolts (check their length before re-use) which are torqued in three stages, initially with a torque wrench and then by two additional 90 degree turns from memory. During these final stages the bolts stretch and feel as though either they are about to break or you have stripped them. It is not a nice feeling and if you are unaware of what is happening you would be tempted to pull it all apart again.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.