The way I read the o.p. they have learned to use the 'standard' arrangement of shifter/brake lever, wrong? Kind of like someone who 'learns' to drive with their left foot on the brake and the right foot on the accelerator. I'm not sure why they mention their index finger on the bars. You brake with your index and middle finger (ring) on the brake lever. You also shift with those very same fingers. Length of brake lever and/or shifter paddles is irrelevant because they have the same origin point. The length of shifter paddles seems very constant between models/brands to meb but I've never really noticed. The classic 2 finger lever is an Avid FX5. I have a cargo bike with the Acera shifter/brake lever combo and have zero issues using it. One reason might be that I have the whole works tilted ... IDK 30° down from horizontal. Puts the levers/paddles where you can operate them efficiently and get your fingers away from them as necessary. Also puts the viewing window right at the top of the bar (intentionally?) so you just glance down at it. Or can, if you can actually see things like gear displays, which I cannot.