I am attempting to build a simple tester for my nephew. It is a bit of a gag in that I am building it on a CR2032 battery holder. My electronics theory is rusty and I have been scouring the web for info. The tester is a continuity tester and a 6v/12v battery low-voltage tester that uses an LED as the indicator. My question is this: do I calculate the resistance for the overall expected voltage in the voltage portion of the tester? Please refer to the schematic I have attached. The LED is an NTE30035/2.4V/25mA. The switches are SPDT. I appreciate any and all help. Also, I thank you in advance for the help.