Trying to find a “small” or “mini” wireless 319.5 shock sensor. The ones I am finding online are beasts. Typically 5 or 6" long, and then typically over an inch wide and deep.
To go with a shock sensor that has a smaller visible footprint, it may be good to look into using a wired shock sensor as they can typically be pretty small comparatively, such as the 5150W, connected to any wireless sensor with a wired input like the RE101.
The RE101 could be hidden behind window coverings, and the 5150W would be attached to the window glass.
There are no mini versions of wireless shock sensors that I am aware of. The 5819S is a Honeywell 5800 series 345Mhz sensor which is not directly compatible with Qolsys panels. You would need a wireless translator like the RE524X in order to use it.