After reading about oil changes I think I may just take it to an indy for fluid changes. Not keen on DIYing the messy stuff.
I do that sometimes for engine oil/filter (I supply the filter and have shop that has good price on the oil do the change). Other times I do it, but even with extractor, have to crawl under car
My other cars can all be done from above.
Going to Indy, at least for first service,might be an idea. Especially if you want to change engine oil/filter, diff oil, brake fluid, Transmission fluid/filter, coolant. Lot easier for them up on hoist. But for these old cars, an Indy who knows these old Benzes is needed. I do a lot of stuff myself, just because I don't trust our local shops to work on my old cars. PS fluid is easy enough to do. Just suck old fluid out, change filter, refill, run, turn wheel back and forth, repeat a few times until fluid looks clear. Manual says to use Dextron/ATF, but ATF has changed over the years. I buy PS fluid because it has additives needed for steering systems.
Make a list of the fluids you want them to use. You will get a lot of opinions on those!
(For a car that, like mine, will sit in storage for long periods, I would use a good synthetic oil. It seems to stay on cams and be there when you next start car (got that tip from a long time Mercedes shop owner/mechanic). Valvoline Zerex G-05 for coolant.)