I like to split the vocals (and sometimes an instrument or two) into two channels, so that I can feed them to the monitors with no compression.  (The individual strip EQ that this provides can be handy as well.)  Doing this with standard mic wye cables makes for quite a rat's nest in the doghouse, and can make repatches quite a chore.  So I made wye cables on which the input and one of the outputs is a single connector.

Start with a Neutrik NA3FM XLR female to XLR Male barrel connector.  (Switchcraft makes one too, but it's a lot longer then the Neutrik)

Procure some skinny two core screened cable.  Mine came out of Horizon Studio Series snake cable.  Each wye will require a long length of cable (I used about 3.5'), plus one a few inches long.

Drill a hole (large enough for the cable you have chosen - and don't forget to deburr the hole) in the female part of the casing just past the threads.  I placed the hole at about 4:30, because at 6:00 the cable blocks access to the console connectors that are below he mic inputs.

Solder the cable to the female connector, along with the short length that will connect the female connector to the male connector.   (On the short length, you can separate the shield and the conductors, they do not need to remain intertwined.)

Slide the female connector into the casing, and feed the long cable through the hole.  (Put a tiny wire-tie on the cable just inside the casing,to act as a strain relief.)

Connect the short cable to the male connector.

Slide the male connector into its casing, and screw the barrel together.  Tighten it such that pin 3 of the male is on the bottom, to match the alignment of the female.

Connect a male XLR to the other end of the long lead.  (To avoid any possibility of a ground loop, do not connect the shield at this end.)

Color code each wye at both ends and at several points along the cable's length, so that when you need to repatch, you can make sure to get the right one.