Ideal bodyfat is a tricky one.
The US Navy has a chart, and so do HM Forces. They are different.
I have found 'A1', 'Thin', 'Slim', 'Excellent', 'OK' and 'Trim' amongst descriptions varying from 12 to 22 %.
Each has a frig-factor for age, which complicates matters as the skinfold curves are non-linear to start with.
Slimguide calipers also have a recommendation.
As a guidline in our world, a Pro cyclist is typically 8 - 12 %.
Incidentally, I heared that the average waistline measurement of 18 - 25 year old women has increased by 1" per decade from 1945.
It was 26" then and 32" in 2005. The fashion industry have reluctantly accepted this. So have 18 - 25 year old men.
PPS. Bioimpedence measurements at home are not worth the steam off my p**s.