It appears that Canada Scott 174 plate block may be the easiest to find with this variety so far.
Then, it may be Canada Scott 176 plate block as is shown below but it is harder to find.
The hardest to find so far may be Scott Canada 175 plate block with this variety.
Has anyone seen any Canada Scott 175 plate block with extra vertical perforations?
Checked many Canada Scott 175 plate blocks and have found none with this.
Also, checked many Canada Scott 203 plate blocks and found none with this.