My hesitance is because it is an idea that, while feasible, comes with a number of limitations that the average user might not recognize when perusing this thread (even aside from the debate that bi-amping can often generate). Speakers must be bi-wire/bi-amp capable, receiver must support a "5 stereo" mode (which the 1070 does, of course), sources must be restricted to PCM or analog, and once it is set up no other mode can be used. Leave any of these out, and the approach either can't be used (speakers that aren't bi-wire/bi-amp ready) or will result in modes where the resulting sound is "broken." If the individual understands those limitations and is willing to accept them (as you appear to do, although I was not familiar enough with you to know that at the start of the post), then it is a "safe" experiment. Would I recommend it as common practice for a surround receiver and a typical user? Absolutely not.

By the way, I assume you've set the speaker distances the same for both mains and surrounds (I'd actually set both to zero if it were me). That just occurred to me as I was typing this post - thought I'd toss it out there just in case.