The Individual Batch Limit is only required when Enable Chaining is turned ON.
If chaining is OFF, the batch limit field remains disabled and is not used. 
PS: View Drag, Drop & Upload Files to Amazon S3, a Salesforce AppExchange app for moving files from Salesforce to Amazon S3: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3000000B5ZPqEAN