SPHINX: Indexer --rotate syntax and multiple main+delta schemes.

[ReX357]

I am setting up Sphinx right now and have a few questions. I have 2 different indexes
with main delta schemes setup. So basicaly my conf file looks something like this:

source jobsmain
{...}

source jobsdelta : jobsmain
{...}

source usersmain
{...}

source usersdelta : usersmain
{...}

Questions -

First off, is having to main + delta schemes in the same conf file valid?

Second, I am setting up crontab to update my delta indexes every 5 minutes. My cronfile
looks something like this:

*/5 * * * /usr/bin/indexer --rotate --config /etc/sphinx/sphinx.conf jobsdelta usersdelta

Is that a valid way to have only the delta indexes updated? Or do I need to make two
separate statements for each delta index? Something like:

*/5 * * * /usr/bin/indexer --rotate --config /etc/sphinx/sphinx.conf jobsdelta
*/5 * * * /usr/bin/indexer --rotate --config /etc/sphinx/sphinx.conf usersdelta

If I need to make two separate statements, is the indexer gonna be busy already
fulfilling the first request? Am I gonna have to set a delay on the second request?

Thanks in advance