David,
If I understand your question, no, that is not going to double the power into the speaker. I am going by what I have read (here and other places) and gleaned from studying associated literature, I am not an EE, but this is my understanding.
There is an amplifier bridging technique that puts both channels of the amp in series, doubling, or exponentially increasing the power of the now mono amp. Some amps are designed for this (Classe') and some will get unstable (my Arcams).
What you are trying to do is not that kind of bridging. You are trying to duplicate the preamps output into two channels for each side (and "bridging" may be an incorrect term in this circumstance). You may have impedance issues, duplicating the preamp signal into two inputs, that will affect the sound (tilt it one way or another) but I don't know enough electronics theory to predict the outcome using your components. I can't imagine it causing any damage.
What vertical biamping is supposed to do in a passive or active configuration is reduce the load on the amp power supplies. The bass generates the heavy load and that load is now divided between the two amplifliers. Most amplifliers use a single power supply to drive both channels.
What I meant by "if you turn up the gain" is the Paradigms seem fairly efficient and might not take full power from the amps. Don't turn it up all the way at once.
There are a lot of folks here that really do understand the theory behind these concepts and you can requery if you have concerns.
P.S. - don't forget to remove the jumpers on the speaker terminals.
Jim S.