If you are actually choosing leads, you are already ahead of a lot of telemetry nurses. Many couldn't monitor v6 if asked. Many believe there is a "V Lead", and it sits in the middle of the chest. (Same applies to ER, and less frequently, ICU.)
Most nurses don't even know the difference between a lead and an electrode. This confusion is actually furthered by the AACN literature, as well as anything else that refers to a "5 lead system", or a "3 lead system".
A lead is a view of the heart. It looks at the electrical pathway from a particular direction of travel.
There are 12 leads commonly used to monitor the heart. There are a bunch of other leads occasionally used, including v4r, v7-9.
Most of us use a 5 electrode system, sometimes called a 5 lead system. At any given time, the "5 lead" system can display any of 7 leads. I, II, III, AVL, AVF, AVR, and a choice of v leads.
As a nurse, you can choose which v lead the machine will be monitoring by choosing the placement of the precordial (brown) electrode. You can then choose any of 7 leads for the machine to display. Often, you can choose for the machine to display 2 leads at once.
Most nurses don't really care which lead are monitored or displayed. The overwhelming majority of the time, any lead shows us what we want to know: too fast, too slow, or not beating. But, when you r monitor alarms V-tach, it sure would be nice to know that the patient has a rate dependent bundle branch block. Or, if you knew your patient had had an event resulting in some ischemia to the lateral wall of the heart, you might really want to watch v6 for elevation.
It cool stuff to know, and fun to learn. I am not an expert b any means, but I enjoy studying the stuff, and periodically pick up on an important change in patient condition.