110w / 12v = 9.17 amps of draw. Stock was 60w/12v = 5 amps.
Another thing to take note of is the light control switch's rating which I'm pretty sure has no public ratings, however honda used the same design of switch for most atvs, so the one with the most lights that I can think of is a 450 foreman or maybe a 680 rincon.
450 foreman = 25w x2 + 45w and 5w x2 for the tail lights so 105w total
680 rincon = 40w x2 + 5x x2, or 90w total.
Seems the upper usage for the switches is about what you're using, but pretty sure the switch should be heavy enough for the draw.
According to this link, you're pushing the limits of the 18 gauge wiring, but should work fine. I'd keep an eye on the wiring and listen to make sure the head light switch makes good contact when you switch the lights on. If you wanted to help the wiring out slightly, you could run your own ground wire that's heavier directly to the headlights, the headlight switch only works with the "hot" wires white and blue.
https://www.securitypower.com/Other/...ation_Note.pdf
If you add a connector from the main harness to headlight wiring, make sure it can handle the amps, pretty sure you'd be safe with a 1/4in spade. The stock headlight uses a "H4" connector which uses 0.312in terminals. Here's a link for the right connector if you wanted to plug and play with your existing harness. For ease of building it, I'd say use some 14 gauge wire on the 3 terminals about 6in long, then splice both headlight wires to each related wire for the H4 connector, so it kind of makes a Y shape. Don't forget to use adheasive heat shrink to properly seal the splice, and you'll likely want to solder the wiring together unless you have the proper crimper to crimp splice terminals (the site sells those too).
http://www.cycleterminal.com/headlight-connectors.html