It's non of the two mentioned T-screws. If you compare it with this PDF https://hollandbikeshop.com/images/591018_proride_en_03_2015.pdf it's the part number 52543.

Dimensions given by the manufacturer: 367x96x165 mm

Unfortunately, I couldn't find this information anywhere at the manufacturer's or on the web in general. With a bit of luck, someone else will answer your question.