Definitely take the entire right turning lane, but you still did very well IMO. Unless you're surrounded by race car driver wannabes, you can easily turn in the lane without really getting in anyone's way. Most cyclists are likely to make it across an intersection before the cars do. They may occasionally get pissed when they see you in the lane, but they have no reason to be and they'll be able to tell what you're planning to do. I also wouldn't worry about going slow up hills. You'll look slow to drivers whether you're going 10mph or 20mph, and as long as you're obeying the law they can get over it. Some places do have slow-moving vehicle laws, but they usually involve narrow stretches of two lane roads where the faster vehicles have no chance of passing the slower ones for some time.