Eman, if you have the VC Encore the 6" probe is fine it will stick out the back a little but you can support it with the hardware VC included with their temperature gauge. I had some thing metal "string" I wrapped it around just to make sure it stays in place.I see your probe tip is about the center of the catalyst. I will see if I can find a thermocouple probe that's a right angle style that won't stick out as far. There's nothing on the back of my stove to support it.
@Jason79er see attached pictures. Also, I linked what you need to buy below to the AUBER website, courtesy of @Woodsplitter67