Traits

Long feelers would come down to the paca's feet in height (or shorter).  For snekkets, this would be feelers that reach no further than their hind legs.
These include animal ears, simple objects (fruits, vegetables, etc), and basic wing-like feelers. Not included; bat wing ears, very complex shapes.
These do not have layers or holes. A rare pacapillar can have5-9 head feelers arranged in any way as long as they are around the head feeler area.

Short feelers that are the length of the paca's head (or shorter!). For Snekkets, they must be no longer than their head.
These are simple shapes, including but not limited to; teardrops, cones, ovals. Not included; animal ears, wings, objects.
These do not have layers or holes. A common pacapillar can have 2-4 head feelers arranged in any way as long as they are around the head feeler area.

Very long feelers can exceed the paca's head to feet length. For Snekkets, these are feelers that extend beyond the hind legs.

These are all other types of feelers, including but not limited to: Feelers with layers, holes/tattered looking feelers, bat wings, complicated shapes. An SR Paca can have more than 9 head feelers.