Saddle for the Mature B-Boy

i may be talking out of turn but its the saddle in relation to sit bones, no? also position on bike and the right minue adjustments for the length of your thigh / and below knee?
I could be wrong..

Finding the right saddle seems like all manner of dark arts tbh. This thing about sit bones though, the wider your sit bones (arse) the wider the saddle should be, right?