Noob chronicals - plumbing questions

[IanWR]

I think in the first paragraph you are meaning drains, but saying returns. You have 2 drains, just set it up as a herbie. Do not t them together. One line will be your full siphon, put a gate valve on that, somewhere easy to reach. The other one will be your dry (or mostly dry) emergency line. Done correctly you will have a silent drain with no bubbles in your sump.

As for your return, drill if you like, or just over the top works fine as well. You can paint that section of pipe black if you would like it to be less visible.