Daf Yomi - Yoma 55 - Kapores.... Thick or High?

Reb Dovid Meyers in his Sefer מלאכת המשכן וכליו poses a shaila if the kapores was one tefach high, but was not solid or was a solid tefach thick. He attempts to bring a proof from our Gemora which states that the kohen gadol would not sprinkle on the kapores, rather כנגד עוביה של כפרת and the word עוביה generally denotes a thickness and not just a height. However, he quotes Rabbeinu Chananel who had a version in our Gemora כנגד טפחא של כפרת.The interested scholar should analyze his sefer on page 74.