In a warm climate like yours the series plugs although not as fast as the others can work fine. I live up in eastern Canada and except for the more serious part of the winter where the car is not used anyways they are fine.
They are present in a 1977 300d of mine. Also in general I suspect they might have a longer service life.

Always carry a jumper in the trunk. It does not matter what one burns out. You just keep applying the jumper across each glow plug until heat is sensed on the squiggly lines. No harm is done by this proceedure as well. I suspect it does not really get all that cold where you live. If you carry a meter makes it even easier.