A caliper cover should fit without issue. Reason I say this is, because the covers are made of thin material and are designed to fit there. They are probably 1/4 (or less) the thickness of your finger.
Personally (and this is strictly my opinion), I think the covers are kind of tacky. They don't look very good. I agree with GdD (in comments). Painting them would be a good alternative. Paint, even done right, won't last but a couple of years. An even better alternative would be to get them powder coated with the color of your choice. Powder coating is very durable and comes in many different colors/styles. You have to have your calipers rebuilt in the process of getting it done (seals have to be removed and cannot be reused), however the outcome of getting it done is usually very good.