What off flavours do you associate with over-pitching?
I try to pitch 1.5 million cells per millilitre per degree Plato into my lagers. I recently read that if you are going cold you could go 2 million. On their product sheet, Saflager recommends up to 300g/hectolitre at 9 degrees Celcius (48 degrees; I often go cooler than 48 with that strain). So that's 60 grams, rehydrated, for a 20 litre batch (5.25 gallons).
Conventional wisdom is 20 billion cells per gram. 60 grams is thus 1,200 billion, or 1.2 trillion cells. That's a pitching rate of 4.8 million cells per millilitre per degree Plato for a 1.050 beer, more than three times what I use, which itself is on the high side of most recommendations.
Moral of the story? You're not going to overpitch your lager anytime soon. I don't see any reason to get ridiculous with the pitching rate. Underpitching is a far greater concern.