von Ken Task.
A finely tuned DB server is key to experience/performance of moodle. So with 2 instances of moodle even if one is not used as much as the other, would mean tweaking is needed for DB performance.
If you can't install, someone can ... contact that person and ask they install and run MySQLTuner.pl. + make whatever tweaks for changes to config of DB server it recommends ... in the areas mentioned previously.
Do that first before seeking bulk ... cause those will fail if DB isn't performing as it should. And in your situation, that's the last thing you need at present!
'SoS', Ken