I also found it most logical to use the existing aux lighting harness.
This connector set is needed to wire to the aux lighting plug. You just push the pins into the connector and then solder to the back of the pins.
3P090WP-MT Connector Set $4.49 ea
http://www.easternbeaver.com/Main/Elec__Products/Connectors/Sealed/SM-MT/body_sm-mt.html
This handlebar switch looks great to the right of the high beam switch and fits in like it belongs.
Item# HBSW $19.95
http://www.easternbeaver.com/Main/Elec__Products/Switches/switches.html#BARSWITCHES
A couple of reusable cable ties may be useful.
Cable Tie Chassis Clip CF-29 $0.59
http://www.easternbeaver.com/Main/Elec__Products/Tabs/tabs.html#cf29
Eastern Beaver is wonderful.
I used PIAA LED fog lamps because they are wide angle and nicely fill the void under the headlights. Generally I turn them on whenever approaching an on-ramp, because the stock headlights are almost useless in tight turns. The lamps came with a decent quality wiring harness.
Yamaha of Cucamonga
#DBY-ACC56-24-08/515400 PIAA Under Headlight Mounting Kit $42.08
#DBY-ACC56-24-05/515397 PIAA LP530 LED Fog Lights = $267.71
FDX FedEx Ground $15.90 Taxes: $24.00 Total: $349.69
Attached are some bad spur-of-the-moment pictures.
Cheers.