Using water-filled milk containers (1, 2 and 3 litre for weights of 1,2 and 3 kilograms) to hang on the lever arm.

The unloaded lever arm creates a 1.5 Kg downward force which is constant and is added to the multiplied weight;  eg., 1 Kg x 9 + 1.5 Kg = 10.5 Kg.

 

 
Weight on lever arm Force @ x5 Force @ x9
0 Kg (just the unloaded press) 1.5 Kg 1.5 Kg
1 Kg 7.5 Kg 10.5 Kg
2 Kg 11.5 Kg 19.5 Kg
3 Kg 16.5 Kg 28.5 Kg
4 Kg 21.5 Kg 37.5 Kg
5 Kg 26.5 Kg 46.5 Kg
6 Kg 31.5 Kg 55.5 Kg

So, this what that looks like:

1 Kg load on lever

pivot set at 5 x

2 std 1kg load 1 Kg load - 6kg force delivered

3 Kg load on lever

Pivot set at 9 x

6 std 3kg load 3 Kg load - 28kg force delivered

4 Kg load on lever

pivot set at 9 x

B1 std 4kg 4 Kg load - 38kg force delivered
     
     
     

Considerable forces safely and reliably delivered.