After I got home, I developed Mr. Brown in XTOL at 1:1 for 9 minutes at 20°C. I just finished scanning in the negatives on my Epson V700 photo scanner. To say I am impressed with the results would be an understatement! The film is on a very strong and thin mylar base, and lies beautifully flat in the scanner. No curling, cupping, or other problems. It scans beautifully. Based upon my results, I may be tempted to try a roll at ISO 12 under similar situations.
Long exposures of water without using a ND filter is a plus, and this film warrants more experimentation.