I've recently started tire shopping myself and come to the conclusion that there are very few front 110/80 - R18 tube-type tires available.
Be careful what size you go with as you may need to make fender mods to get them to fit if you go larger.
It would be nice if there were a list someplace of what tires people have used and which sizes fit without mods. Also whether the tire is tube or tubeless and if it is tubeless if the manufacturer has okayed it for use in tube-type applications.
Keith