Sorry, but you know the guy from Silverlungs did not know what he was talking about.
The larger surface area of the silver means that less silver is stripped away if the current remains the same for both large & small bars.
What he should have said is that the larger bar allows for a higher current that can speed production. Do they allow you to increase current? Or is it fixed? Don't you want control over the current with all the money you will be spending?