The carbs are only intimidating until you clean out the first set, as you figured out.
As for the overflowing carb issue, chances are it was just a sticking float caused by sitting for so long. My K1 will leak the first time I turn on the gas if I let it sit for more than a couple of weeks, or if I let the bowls run completely dry. Tapping on the offending float bowl with a screwdriver handle always takes care of it. My last day off I pulled the carbs and polished the float hinge pins to a mirror finish. Hopefully that will keep them from sticking in the future.
Near sea level, jetting and needle clip changes shouldn't be necessary on an otherwise stock bike. Does your K1 have any non-stock intake or exhaust components?