Lagers are what I brew most of the time. I've never had an issue with the sulfur by-products entering back into my fermenter. I wait until I know that the krausen isn't going to enter into the cold crash guardian before I use it.
This 8 minute instructional video helped me a lot.
Is it just my area or is it difficult to locate Hacker-Pschorr Oktoberfest Marzen and Weihenstephaner Festbier?
There's plenty of local breweries and even Spaten or Paulaner.