Okay, so assuming I have 2 holes in each overflow, let me ask if you think the following layout would work. In the first overflow, use Herbie's set up with 2 pipes that lead to the sump. One as the main and one as the emergency. In the other overflow, I would like to use one as a main drain and the other as my pump output. Is it a sound plan?
A couple of other questions. Would each of the three drain pipes have to run to the sump independently? What if I only have 2 inlets?
Based on Herbie's plan, does this eliminate the need for me to baffle the sump which could save me space?