I am traveling, so I don’t have my Antarctic countour maps with me, but the west Antarctic ice cap is very small compared to the east Antarctic ice sheet - which is a depressed “bowl” (or huge shallow dinner plate) with the mountains around the raised captive ice. East Antarctica is more alpine as I recall.
The rebound can only be measured (by GPS gages at least) where the bedrock is visible around the ice cap itself. Othereise, you can only drill mile-deep borehole through the ice, them the top of ice and the depth of the borehole. If they didnt, they’ve only measured where the bedrock is squeezed up by increased mass of ice in the center. But that is not the politically corrupt politically funded answer they were looking for to support the CAGW conclusions they wanted.