Generating a set of web tiles from SRTM data involves a careful dance of loading just enough data into RAM to generate the world one "slice" at a time. This is a theoretical discussion of how it might be done. It's similar to what was used to write the python script gen_terrain_tiles_script.py, but isn't the same. Truthfully that python script would be much improved if this document was written first. . .

Zoom Levels

Zoom Level	Degrees Lon.
0	360
1	180
2	90
3	45
4	22.5
5	11.25
6	5.625
7	2.813
8	1.406
9	.703
10	.352

More info can be found on the ​OSM Wiki