Thanks for the reply! Based on the fact that this filter option for "Instant
Checkout Unavailable" does not return any results for my inventory, I am inclined
to believe that your statement about which results it returns is correct.
To clarify, for now I am only looking for those items with a height of 2cm, as
the restrictions for length and width are much larger (27cm+). I can work on
isolating those parts that are too long or wide later, as there are fewer of
them.
I really hope there is a way of applying this filter!