DISCLAIMER: my advice is for E-AB or E-LSA that is already airworthy.
I’m not familiar with any special widgets, however the instructions to define a discrete input is in Section 34.4.26.2.2 Discrete Inputs, Page 34-147 in Rev AB of the G3X Installation manual. There are four discrete inputs available on GEA24, and then another 7 or so general purpose inputs that can be configured as discrete inputs.
I connected my inputs on J244 as follows:
Stall Warning: J244 P40
Canopy Open: J244 P41
Spar Pin Open: J244 P42
Battery Fault: J244 P43
The first two are already configured and selectable in the G3X, the spar and battery are custom alerts that take about 5 minutes to configure.
It’s simply a matter of running the device output wire to the respective pin and then identifying that pin for its alert in the G3X EIS setup page.
The canopy alert is fairly sophisticated with inputs from engine rpm (already present) and the canopy switch position. The stall warner provides a visual alert as well as audible.
The battery and spar I have configured to provide a red alert.
These alerts are displayed on the PFD.