To compare pistons, you have to know the area of the holes. Use this formula
R(squared)x3.14xH=A
Where R is the radius of the piston hole (1/2 the hole size) and
H is the number of holes.
If two pistons have the same area, the one with more, smaller holes will have more pack.
Like this 1.3mm÷2=.65mm=R
.65mm (squared)x3.14x10=13.2665 square mm. 10x1.3 pistons.
.7(squared)mmx3.14x 8= 12.3088 square mm. 8x1.4 pistons.
The pistons have an area of 200.96 square mm
Hope this helps.