I used two different tuning methods, using method one produced 6.10MHz, using method two produced 5.65Mhz. How do I know which one is most accurate?

Method one is the most accurate. The tuning PCB is placed next to the transmitter coil, and the frequency is slowly reduced until the LEDs start turning on. The tuning knob is then turned clockwise about 2 or 3 clicks. The LEDs will be off.

The tolerance of the tuning is quite broad: 500 kHz, so absolute accuracy is not necessary, but of all the methods, method 1 is the one to use if possible.

For more details, please check the link:
https://www.spooky2.com/forums/viewtopic.php?f=117&t=9818