Overfilled tanks - now what?

On our first trip in our new-to-us 2004 2720SL, the kid at the gas station (over)filled the tanks while they were in the horizontal position. I hadn't finished reading the manual yet so I didn't know enough to stop him, and we do have the tanks that say that they should be filled in the vertical position. We didn't realize it until we reached the campsite, but he also broke one of the tank hoses, so that no matter which tank is selected by the regulator, if a tank is turned on there is gas leaking out

The hose will obviously need to be replaced, but what should I do about the tanks? One is reading more than F, the other slightly less than F.
I've seen some people recommend that the OPD be replaced at this point, but my local LP gas retailer said they can't work on the tanks unless they are empty.

What do you think? Should I just drain the tanks down to the appropriate 3/4 mark? What's the best way to do this, preferably without worrying about blowing up the neighborhood (and me)?