My thought is that I would go with the UL2 given how light it is and the added room it would provide. I realize that a pound here and there adds up, but i just think it is important to pick and choose where and when to get picky about saving weight. Looks like the packed weight of the UL2 is less than one lb. more than the UL1. Shelter is something that will have a big impact on how pleasant the overall experience of you trip will be. It may be more than enough room, but better too much than too little