transmission overfill 6 ounces harmful?

[Bruno_300TE]

Hi everybody
I recently changed oil and filter of my transmission (722.3). I added 6.8 quarts to refill - it turns out that was too much: the level reads about 1/2 inch about max with running engine in P at operating temperature. (When I checked immediately after the change, the level was ok - probably the temp of the oil was not high enough to give me an accurate reading.) I feel this cannot be so bad, since it corresponds to about 5-6 ounces only, and it shifts ok. On the other hand I do understand that overfilling the transmission is something everybody warns you about. Should I drain immediately or is it ok to drive till I have access to my friend's garage to drain it?
Thanks, Bruno

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1992 300TE 139'000 miles