Okay here's an easy way to size a bike frame, head down to your LBS and take a look at some bikes there(even if you don't want to buy there). Even if they went let you test fit the frames by hopping on, you should be able to get a general idea from standover, you want the top tube at about 2 inches below your inseam or rather, this is what I have been told and found works for me. As for weight considerations, I'm a very light person myself you'll probably get a much faster/accurate response from the clydesdale/athena forum on that part.