your main drain witch is the shorter one way below water level in your overflow box have it to go into your sock area make sure the valve goes to this pipe and easily accessible to adjust the water level in the overflow box.the second drain pipe have it cut to just over you water level in your overflow box after setting the level you are happy with as this is your emergency drain to anywhere in your sump.
Best to measure your water level by shutting all electricity off and check where the water level sits in your sump mark it on the glass and never over fill your system with RO or water changes.
I have seen people making a hole from the top section of their sump that runs directly into the floor drain as an emergency.
Make sure the glass you want to drill into is fine.As the tank looks a little old or maybe just dirty
Is you are building a canopy then I wouldn't drill the glass as the canopy will hide the pipes.