Daf Yomi - Sukkah 5 - Kapores ...Thick a Tefach or High?

Harav Dovid Meyers, in his sefer "מלאכת המשכן וכליו" wonders if the kapores was actually a solid tefach thick, or was it simply a hollow box. He points out the Gemara in Yoma (55a) which uses the term "עוביה של כפורת"- “The thickness of the kapores”, which seems to indicate that the kapores was not just a tefach high, but a tefach thick. However, there is a different version of that Gemara- that of Rabbeinu Chananel, which actually reads
"טפחא של כפורת"- “The tefach of the kapores”, instead of the thickness of the kapores. For further discussion on this, see page 74 of the aforementioned sefer.