Don't know but size are always the same but different colours

There is a few more factors that will affect the numbers
drawn
1. The moon
High tide the balls will be lighter
Low tide the balls will be heavier
2. Time for drawing of the balls
Fast, slow, fast, fast, slow, slow, slow
Fast, fast, fast, fast, fast, fast, fast
Above is just samples
Different speed of drawing the balls will have different
results
Unless you are always there with a stopwatch and recorded the
timings and numbers or else very hard to calculate
3. Machines' measurement
If you have the dimensions and with a software chances of winning
will be very high
Above are all my personal opinions 