I don't really use lightning but my default tip was 9.8 dogecoin back when the original doge tip bot was on reddit, and that was a common number to pick after doge values went up too much to sustain the previous 98 doge standard referencing dogecoin's nascar driver Josh Wise number 98

64, power of 2 and it’s just over 3x the standard so the recipient can do 3 zaps and still have a sat left, hopefully encouraging more zaps.