[Darryl Ramm]

The Pro Tools LE license is based on the interface, you can install the software multiple times on multiple different computers, its the presence of the interface that enables the software to run.

Rebooting between partitions is a bit of pain, but with an iPhone you should not need to sync very often or at all. You can purchase and update apps etc. over the air. If like me the first mongo-sync will be for gigabytes of music off the mac. In which case you've also got to clone (or at least point at) your iTunes music library from both partitions so you can sync to the iPhone and yet play iTunes music when booted on the other partition.

You don't need to "clean" anything. Just reparation the drive when you install the OS. And to be clear you cannot format/repartition your running boot partition. Sure you can get install media and futz around with two installs from scratch but that is a bit of a pain. A faster way is to use an external scratch drive. Use Carbon Copy cloner to clone the existing install. Boot off that cloned disk. Then partition the internal drive and you should be able to clone back the external drive and then install the other OS X version on the unused partition.

All either way all this work to go sideways,... I'd be upgrading to PT 9. You get interface free-flexibility and just advancing an upgrade you would be doing anyhow in future.

Darryl