To tile global at this high of resolution you cannot use the shape model as the base (initial) topography. Hence you have to make a Zmap, which is really just a bigmap whose filename starts with a "Z". Then you can tile each bigmap using BIGMAP tiling. To make the Zmaps you need to have a list of all the maps you wish to use. At the lower resolution you don't need to use all the of Zmaps, and at the pole you need to use even less because the Zmaps will start to overlap each other.
The Zmaps will be "ZN" or "ZS" for the first two characters. The next two characters will be the latitude divided by 5. So 90lat is 18 and 0lat is 00. The last two characters are will be the longitude divided by 5. So 350lon is 70 and 0lon is 00. So the final Zmap will looking something like ZN1071 which means +50deg and 355deg W (because SPC uses west longitude).