Platforms still request full stacks of construction materials, but in between the rocket leaving the planet and arriving on the platform my mod kicks in,
if at the time the cargo pod approaches the platform it is delivering more construction materials than requested it'll put those items into the trash slots of the silo,
as well as refund the rocket parts you "technically did not use" (rounded down), the silo might exceed the usual maximum of 50 parts stored, but you'll use those eventuallly.

Ideally this mod would have just made "ridesharing" possible, but sending rockets to specific platforms or playing with cargo pods through lua is currently not implemented.