Copying one site to another without users - Joomla! Forum - community, help and support

hello.
i use test site new articles, new pictures, or events, validate ideas. joomla! 2.5.
every 2 weeks copy files , database test site public one. works well.

my new problem going allow peoples create account on public server. can't anymore copy database 1 other.
i thinking copying database not 5 tables "user" beginning name (usergroups, users, users-note, users_profiles , users-groups-map).
but other modules/plugin have tables "users", bet solution not possible.

anyone knows way copy in database user related informations ?
or there no other solution duplicating correct modifications 1 site other ?

if having users registering , changing content in way throw ids out across board if try manually synchronising sites.

i sure there way of doing not know , not believe there extensions available achieve either.

therefore believe conclusion correct one; run tests , development locally , recreate same changes remotely once completed.

obviously recommended full of remote site before doing of changes irrespective of fact worked locally, , if servers match each other in configuration - unlikely.