This is an integer between 0 and 100 that determines how much
"weight" to place on the favored side. A value of 20 says to
increase the chance of rolling the favored number by 20%. A value of
100 would mean to always roll the favored number. A value of 0 will
disable favoring completely, even if a value for "favor" is given.
Are negative values allowed? In other words, could one use this to reduce the throwing of low numbers rather than increase the throwing of high numbers? The documentation says "between 0 and 100" implying that you can't, but it isn't obvious to me why this should be the case.