Bars and saddle level should be easy to achieve with an endurance frame. Look around, talk to people. That won't be too upright, should be fine. It's the usual long distance setup for many riders, even skinny ones. More important IMO is reach. Sitting on the bike, with forearms horizontal, your elbows should either be in front of your knees or have little overlap with them. For some reason, many people buy frames which are too small.