Tire cover sizing with wheel simulators

I'm looking to get some tire covers. The diameter of my tires is 29", and I'm considering this product.

I have wheel simulators which increase the width of the tire by a few inches. (similar to these:
)

Does anyone have experience with a similar product to give me an idea how snugly they fit and if they are likely to accommodate the extra width? If not, I might want to go to the next larger width size to give it more play, but then I'm worried that the overall fit will suffer.

Thanks for any advice.