I forgot to report back about the Pec machine Pete.
You are quite right; the one arm movement raises the weight less than
half the distance that the two arm movement does, which is obviously
the mechanical advantage and purchase ratios we discussed a while ago.
I was pleased to be able to explain it to the gym staff, who didn't
have a clue. But then neither did I until you explained it to me!
My thanks for your help, which proves that we can all still learn
something if we want to. ;o)