How to download complete audiobook to apple watch, not just 5 hours at a time?

I have plenty of room on my Apple Watch and would like to download a complete audiobook, purchased from the Apple store, to the watch in one sitting. So far, however, I have been able to download only 5 hours of any book at one time. If I listen to some of the download, it will then let me sync the watch to my iPhone to download more up to the five hour limit? Is there a way around the five hour default?

Another question which has been posted elsewhere by others: has anyone found a way to download from an iPhone to an Apple Watch an audiobook purchased on CDs, ripped in, and downloaded to an iPhone? I can get the legally obtained audiobook onto my iPhone, but it will not be recognized for transfer to the watch unless it was purchased from the Apple store. Thanks!