welp, answered my own question, but thought I'd post her for the next guy (or gal).
The replacement bulb I bought is a 9003/HB2 H4, rated at 60/55W (non-Silverstar). The wattage seems to be higher than spec (35W I believe), but in the year I've owned the scooter hasn't seemed to negatively impacted the electrical system or battery.
I am looking to buy the bulb listed on ebay to have as a spare since it's rated at 35W.
As far as the removal of the cowl, there is a screw below the headlight in the front cover and 4 screws going through the handlebar back cover. I had to take my mirrors off as well to get the front cover to clear the mirror posts.