HRALXSYNC for Talent Management

We are implementing Talent Management on EhP4. We have activated the HRALX HRAC switch for business partner activation and now need to create BPs for our existing Central Persons. We are using HRALXSYNC to do this. According to the documentaion we should run this with the Employee box checked. We currently have close to 300,000 central persons in our production system.

1) Should this be run wide open in the background? Or do I need to run it for smaller groups?

2) Do we need to run this for all central persons (300,000) or just the ones that are currently active (18,000)?

3) There is a 'Changes Since' option to run this with but that does not allow you to check an object box. Should this be used? I saw reference to this in this post: Using HRALXSYNC to create internal candidates for E-REC This stated that we should run it with the 'Changes Since' box checked (standard variant) and then schedule the program periodically to pick up changes. Is that the correct procedure in our situation? That message was referencing E-Recruiting. If not run for a specific object is this going to create more objects than what is needed for Talent Management?

Thanks for your help!

Leah