Good morning!
(Funny to think we all are in so different time zones: Pacific, Central European and NZ Daylight).
Regarding the chain-ring, I cannot find out how many teeth are there in my 2017 Vado 5 but comparing the cadence to speed I am sure it is 48t. You guys are right to say about the drive-train loads, let me only tell you why, at least originally,
Specialized put the 48t chain-ring. To achieve 45 km/h (28 mph) with 48-11 gear ratio you only need to pedal at 76 rpm which is doable for most riders (as long as you are in Turbo mode, flat, no wind or with tailwind). To achieve the same speed with the 40t ring, you need to be at 91 rpm, which is not easy. I wonder why it would be 40t then in NZ, as the NZ web page of Specialized still reads 48t for model 2020.
For myself, my habit is to start in the middle gear and upshift as the speed increases. My natural cadence is 77 rpm but I tend to spin the cranks faster if I can, to increase the motor support. Nice thing with all Vado displays is the Cadence read-out. I would say the same as the car has its preferable rpm range and you are in proper gear for given speed, the same is with rider's cadence, speed and gears in a bike. That is also easy on the drive-train.
European rules only say the following for "Class 3" (L1e-B) e-bikes:
- Limited to 45 km/h and to 4 kW of assistance
- Registration plate must be visible at all times (so Specialized rear light also illuminates the registration plate with strong white light)
- Two independent, effective brakes
- A bell or a horn
- Rear-sight mirror
There are also rules how many and what lights and reflectors should be used. The rule for Poland related to the headlight is: Not lower than 500 mm and not higher than 1200 mm, covering the road for at least 30 metres in front of the bike. The headlight and rear light shall be on at all times. (Note: my version of Vado even sports the STOP light activated by either brake lever).
As you said before, Specialized change specification with or with no notice. The 2017 model has a 600 lumen headlight mounted on the stem and made the way you can regulate the angle. Interesting, there is a blind window making the top of the light circle evenly cut the way you do not dazzle drivers, and the lamp angle can be precisely set. As I hear, that headlamp has been replaced with a 205 lm Supernova light (true?)