Datawrite Grey is, IIRC, a -R media type with the code "FUJIFILM03"
This media code does not exist in the 811S firmware's tables, which means that the drive doesn't really know what to do with this media type. It will use a generic write strategy and speed, which usually does not produce pretty results.
1/ Download OmniPatcher (see sticky), version 2 (or newer)
2/ If you want to continue to use HS0K, then use LtnFW (see tools collection sticky) to back up your firmware and load the .BIN into OmniPatcher. Otherwise, download the HS0R firmware from http://codeguys.rpc1.org/firmwares.html and load the HS0R firmware into OmniPatcher (you can load the .exe file directly)
3/ Look through the list of -R media codes, and find one that you'll probably never ever use and select it. For example, "Auvistar". Rename this media code (use the text boxes on the right) to "FUJIFILM03" for the manuf. ID and "52" for the rev. ID (be precise with the spelling and capitalization!).
4/ Important step! After renaming the media code, double click on it in the media list. This will bring up the window to reassign write strategies. Based on results posted in the write strategy reassignment thread stickied in this forum, TYG02 seems to be a good strategy to use.
5/ Save the firmware and flash the patched firmware that you have just created.
6/ See if it works now. If it turns out that the TYG02 strategy doesn't work too well, you may want to try other stratgies (trial-and-error).
Edit: Looks like someone beat me to it... read the thread linked to above for more background information... the instructions that I provided in this post will differ from previous instructions posted in this forum because older instructions were from before OmniPatcher 2