Need some design options to extract att records

we have contacts att records.. we would like to bulk extract them and send it to external sytem ... I need ur help in providing some design options, things to consider

1. Uncompressed file is usually stored into temp folder(which we know how to do it), can we do it to different folder

2. Siebel stores the compressed files into the file system, the size you see on UI is usually much smaller than the actual size.. Is there a way we would know the size or may be read the file size after extraction, we want to have control over the size that need to be extracted