[1.6.4] Custom recipe which supports stack sizes

Hi, I'm trying to make a custom recipe that takes into account the stack sizes of the input grid. I've managed to get the output to change depending on the size of the stacks of the input, but I cant figure out how to make the recipe actually use the entire stack from the input. It only takes 1, could someone tell me where I should be looking to make this happen?

Edit:

After some more research it looks like I need to create my own crafting handler that implements ICraftingHandler but I would like some info on the parameters of onCrafting. Im assuming the item stack is the output stack and craftMatrix is the crafting table. Would I be able to use the matrix to edit the leftover items in the table to delete the whole stack of items instead of just the single one it usually does.

Also would this effect only apply to recipes from my mod as the interface comment says its called from a mod container.

Edit 2:

Ok, so I seem to have figured it all out myself now, the only issue I have left is that the IRecipe.getCraftingResult doesnt work on a stack size change. It works when you split a stack or re-seat a stack in the slot, but right clicking into a stack to increment its size will not trigger a recipe update. Anyone know how to do this?