Just to confirm, did I calculate the current correctly for the situation I had, with 2.8V and 10kΩ = 0.28mA? Just making sure I understood the variables.Most LEDs will shine brightly with 1mA or lower. If you connect a 1kΩ resistor in series with the LED and connect it to three D-sized cells (4.5 total) the LED will be amply bright even though the current drawn is much less than 20mA.
And that Joule Thief circuit looks to be exactly what I need to learn for this particular project! Thanks!