As far as daisy chaining the COMmon leads... I first crimped a .187" quick-connect to the end of a spool of wire, then (without clipping the wire) attached it to the COM at what would be the end of my chain. I then ran the wire to the next switch in the chain, clipped it (leaving a little bit of slack) and stripped the end. Then I stripped the end of the (now shorter) spool of wire, twisted the two stripped ends together, crimped a quick-connect on both wires and attached it to COM. Repeat. After attaching to the last COM, run the remaining wire to the terminal block (or the I-PAC in your case, I guess, if you're not using a terminal block), clip, strip, and screw in.
The last pic on my site (of the underside of a joystick) shows the daisy-chained commons