|I assume you mean External USB Hard drives.|
Your post is dated July 27 but just appeared in my Hardware forum. Today is Aug. 2.
Steve, to try and answer your question I will ask one. What do you consider an excessive time frame for you to get the Safely remove message?
If you have sent data to the drive and it has not finished writing that data Windows will not show you the safely remove message.
IMO your settings are counterproductive. Write caching speeds up the drive performance as does indexing.
Depending on the file sizes being written to the drive that could make the difference.
One other thing to note. If you are connected to an older USB port, or to most hubs you are running at USB 1.1. I assume you know what affect that can have on performance with large files.