at verses cron syntax

I am running scripts via cron without issue but I have a need to run something similar with at. I am sending 2 arguments, XYZ and 1, to my script. My working cron line is Code:*/2 0,1,3-23 * * 0-6 /usr/bin/sh /home/user/dir/script.sh XYZ 1 >/dev/null 2>&1 The script writes an output file in /home/user/dir/ and the script uses full, not relative, path definitions. I have tried a dozen different variations of my working cron line, as the user and as root, with no success and I've also searched high and low but I am finding it very hard to find any relevant information using "at" in searches...go figure.

Please save my sanity!