Oracle hot back up script

Hi
I have a simple unix hot backup script which puts a tablespace into backup mode, copies the unix file, then ends the backup mode and continues on for all the tablespaces.
At the end I then compress all the copied datafiles.  Can I compress the datafiles as I go along? I am having trouble with disk space.
It can take a long time to compress some of the really big ones and so would there be any problems with a long delay between the hot backups of each tablespace?
example of existing script:
alter tablespace WEBS begin backup;
host echo 'Starting WEBS data backup'
host cp /local1..../webs_data01.dbf /local3/..../hotbackup
alter tablespace WEBS end backup;
host echo 'End WEBS data backup'

alter tablespace WEBSINDEX begin backup;
host echo 'Starting WEBSINDEX backup'
host cp /local2/......../webs_index01.dbf /local3/......../hotbackup
alter tablespace WEBSINDEX end backup;
host echo 'End WEBSINDEX backup'

I would like to change to this:
alter tablespace WEBS begin backup;
host echo 'Starting WEBS data backup'
host cp /local1..../webs_data01.dbf /local3/..../hotbackup
host gzip /local3/...../hotbackup/webs_data01.dbf
alter tablespace WEBS end backup;
host echo 'End WEBS data backup'

alter tablespace WEBSINDEX begin backup;
host echo 'Starting WEBSINDEX backup'
host cp /local2/......../webs_index01.dbf /local3/......../hotbackup
host gzip /local3/...../hotbackup/webs_index01.dbf
alter tablespace WEBSINDEX end backup;
host echo 'End WEBSINDEX backup'