Still mulling over the “street classic style” idea. Nightster and 883 I do not recommend. Not impossible to learn on but the odds are against ya a bit more then normal.
5’7″ and they are too small for you… nah don’t see it. I am 5’10’ and started on a Vulcan 500. Compared to length, and power its smaller then the nightster and 883. Someones trying to get a comission of ya.
The only right advice anyone really can give is to sit on anything and everything you can and find whats comfortable for YOU. Leave the ego at home, heck leave the friends at home if they can’t be more concerned for your safety rather then their “cool factor by proxy”.