Outlook bi-directional Sync

Hi,

We are planning to implement Outlook calendar  bi-directional sync for in one of out application using EWS SOAP services . It should sync appointments from outlook for thousands of users using batch job. Here is the approach we through of.

1. Using SyncFolderItem we would like to get calendar items in batches (25-50 per batch) for each user and call GetItem to retrieve Data.

Is it the correct approach?

I looked at Subscriptions functionality in bulk upload, looks like it will be best suited for individual user  sync and not for bulk users sync. did any one implement subscriptions for processing sync for thousands of accounts.