A couple questions about alchemy elements

[PrinceYumil]

I've been saving all the elements I've found so far, and I currently have a couple elements in stacks of 1800-1900. How large of a stack can you make before it starts a new stack? Void Rondos stack up to 5000, is it the same for elements? Will I be able to sell stacks this large in the stall network? If not, is there any way to split up a large stack into smaller stacks?

[.AWAKE.]

elements can be stacked upto quantities of 5000 or less
which is the best way to buy them through stall network anyways