Back in the day I picked up a complete sheet of #610 so all the errors are there. How would I figure out a value for the sheet? Do I just add up the error prices plus plate blocks or is there a catalogue somewhere that would give a sheet value. I'm not particularly hung up on values since my stamps will not be sold until I am ashes, just curious. I used to collect Canadian errors at one time and have most of the common ones from that period. It started to get crazy when I was picking up colour donuts and other insane common errors!