Yohann iPad stands are made for uncovered iPads only and do not work with any fixed protective case. There are two reasons for this.
Many cases on the market vary in thickness and shape, and it is impossible to make a Yohann iPad stand that fits all.
We think the iPad is a beauty in design and material itself and should not be covered by a cheap-looking protective case. We recommend a loose sleeve like the Apple Leather Sleeve to protect your iPad when traveling.