I'm currently shopping for a new bike and have pretty much narrowed it down to a Madone 5.2 or a Scott CR1. The problem I am having is getting appropriate sizing advice. I am currently living in Singapore and there are limited places to shop. So far, I have been told my frame size should be 56, 54 and anywhere between 51-53. I am pretty much started out and want to make sure I get a good fit but it doesn't look like I can rely on the shops here. Is there a resource where I can get a good idea myself, at least for frame size?