Hello MPires,
partially were your questions already discussed
Looking for a Shhortcut to a Great SX
Re: Compact front & rear lights
“The crucial factor whether a saddle fits on the molding or not is the distance of the saddle rails to the the lower edge of the saddle nose, as you can see below.”
Strida-5 24/7/365 - Long distance mods & living with the bik
The Strida “EVO red 18 inch and leather” - that’s the Canadian custom edition - 
is originally equipped with the ST-SDL-003 leather saddle.
http://stridacanada.ca/?product=strida-evo-red-18-inch-and-leather
Looks like the Strida saddle would fit, no?
(At least with the QRS system.)
Perhaps could Bill tell us more?