After may tries and failures of using a normal copy by dragging from drive to drive, I found that the only way to copy my old Time Machine database from my old drive to my new G-RAID mirrored drive was to use Restore in the Disk Utility. Old Time Machine database as source and destination was new G-RAID drive. Worked great
Thanks for the great feedback.
Time Machine is a tricky piece of software, it does require essentially a restore to another volume in order to work properly