Sounds good, yes block to heater pipe on OM606 is the same as per sixto says on w124, by oil filter housing, but it's a steel pipe on 606, you would have to cut it down and replace with rubber to tee it. Or get the 604/605 pipe which is shorter.

Good idea leaving the cabin heater on so the block heater heats up the interior!

Got pics?

Beers, H