That answers my concerns, but now all you are doing is changing the series from 47k to 94k. I don't think that is what you intended.
The way the typical Fender works, is in the high gain jack, your two 68k resistors wind up in paralle, and the resulting 34k resistance is in series with the input signal. Plugging into the low gain jack, puts the two 68k in series, one end at the inpit, the other end at ground, and the center junction is the signal feed into the amp. That is a 1/2 voltage divider, and drops the signal voltage to 1/2.
I think that is what you are trying to do, and rally, changing the total resistance of the 820k is one way to go about it. Try this, wire one of your 47k in series - that is from jack to grid. Then try tacking or just clipping some different resistors across the 820k, just to see how it reacts. In fact you could remove the 820k and tack in something like a 1 meg trim pot wired as a variable rsistor. The turn it up and down to see how it affe3cts the stage. That would let you come up with some different resistances that would alter your voltage divider. Note what settings of the trimmer seems to give you the two levels, meaure the trimmer at each setting, then we find resistors close to those values.