Answer: I'm afraid I've never heard of the "Wall Of China" shrub/tree. I believe the only way to contact the company for information is via mail.
Heavy clay is a challenge...there aren't many plants that thrive in such conditions. It may be worth the time and effort to improve the texture and drainage of the soil with organic amendments of grass clippings, shredded leaves, compost, and/or rotted manure before you begin your planting. Amend the whole strip, not just the planting holes. Otherwise, it will be like planting your shrubs in underground clay pots of rich soil, and they'll get potbound and soggy.
If you don't have the time to amend the soil, try Japanese Snowball bush (Viburnum plicatum tomentosum), and/or weigela. These are deciduous, so won't provide a visual screen in winter, but with clay soil, there aren't many options. Another option may be white cedar, which naturally thrives in woodland swamps; but woodland soil is humusy and porous, not like clay. Ask a local landscaper/nusery person if they think white cedar would grow well in your soil (it helps to have someone on site to judge the soil's condition). I hope this helps!
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