John, Love the topic....
i like your scale.....going to take a shot...
1 = unique
1-3 = impossible
3-5 = ultra rare
5-10 =very rare
10-30 =rare
30-50 =scarce
50-70 =tough
70-100 =very difficult
100-200=difficult
200-500=tougher
500-600=less common
600-1000=common
1000+ why bother
