I have a couple of questions about these bikes.

First, the specs on the motors of the regular Vado and the SL aren't clear. Both are 240-250W motors, but the Vado is supposed to supply "4xYou" and the SL only "2xYou". The regular Vado does list a higher peak output, though of around 500W. So, is the regular Vado only able to supply the 4x in short bursts? Is it able to supply more power because of the larger battery in the Vado?

The next question is on sizing. I am 5'9" and have ridden in the past a 54cm Cannondale road bike with drop bars, but now I'm looking at a Vado SL to give me a boost to get back into biking more. The salesman at the store looked at me and said that I should get a Large, but the chart on the Specialized site says that a Large is for 5'10" and up and I should be on a Medium. He told me I was crazy and that I was taller than him and he was 6', which I just don't get - as if I don't know my own height. (And, since I've shrunk in the past couple of decades I did check the night before I went in there when I was looking at the chart and, yes, I'm 5'9" down from 5'9.5" when I was younger). His assertion that he could eyeball my height better than every measurement I've ever taken is silly, but perhaps this was more of a case of him thinking I looked like I belong on a Large and the height numbers were just idle banter to back up his assessment. I will have a test ride, hopefully before the weekend when they get done uncrating and building it, so I can double check, but I'm not sure I'm the best expert in knowing if a bike is the right size for me in terms of whether the M or L is better. Are there rules of thumb to help me gauge if the size was assessed correctly when I do my test ride? Any anecdotal evidence of what the right size would be for a 5'9" person? The only other factor is that I'm carrying quite a few extra pounds - around 270 lately - but I don't think that should affect bike sizing...?