I've just biamped my Acoustic Energy Evo 3 with an Arcam Alpha 7 integrated amplifier and Arcam 8P power amplifier. When i turn on the integrated amplifier only (which runs the tweeters), it seems to need very little amplification, whereas the mid & bass which is run by the 8P, produces much more sound so needs more amplification.
The conventional way would be to use the more powerful amp to drive the mid/bass driver, but in the past, a few manufacturers did recommend trying things the other way, so you have the more powerful amplification driving the HF. The reason for this was so that the higher frequencies were being driven and controlled by amplification that was more stable and consistent at higher volumes than a lesser powered integrated amp.
Try it both ways and see what you think, it will partly depend on the speakers being used.