To test the customization facilities without uploading to homer:

1) Create a subdirectory under sessions/ called '000' ('001', etc).

2) Set the following shell variables:

 export REQUEST_METHOD=GET
 export QUERY_STRING="customize=x&delivery=tgz"
 export HTTP_COOKIE=session=000

3) Put an appropriate choices file in 000/

4) python matrix.cgi

