Yeah I played around with the different pins using the same weight. The only difference I noticed was that the loading pin furthest from the lever provided the greater resistance, which as you say is to be expected re simple levers.
I lifted the huge amount of 10kg per leg for 4 x 20 and it destroyed my quads. I`m not soft by any means but doing it slowly and correctly with less weight provided much more muscular pain than from flicking a heavy weight up and down.
Seatbelt was applied for the last couple of sets and added an extra mental cue to keep the tension constant and remain in the seat.
I`m really impressed with the smoothness of the machine in general. I have seen a few Hammer Clones on the gymdirect website which have caught my eye.
Any other hammer machines that you have used that you enjoyed?