Thanks for the information!
No link on the site links to a product without /category/subcategory/, so the chance is small that a visitor gets the 'wrong' page on his screen. So you suggest not to worry about this ''duplicate'' content, also because the canonical tag fixes it? I will also watch the videos btw

However if I try this with my setup and remove the main category and just leave the sub-category in the url - I get 404 errors
I don't understand what you mean with 'my setup', could you explain the error you get

? Is it bad?
offtopic:And what about text on product pages (like 'description, Serie, Brand, Shape, Color') etc. I have hundreds of these same product pages, only with different products, is that bad for pagerank when it comes to duplicate content?
Thanks in advance! Kind regards, Mike