Horamkhet,
The flat plate design of the Washington-Franklins measures 18.5-19mm X 22mm and the design of the flate plate 2c Harding measures 19.25mm X 22.25mm so you would need to use a template from the flat plate 2c Harding as chasa suggests.
The 1847USA.com site suggests an alternative template method:
Quote:
Another template method for those who do not wish to cut a stamp in half, is to simply scan a known flat plate side-by-side with the candidate rotary sheet stamp. Bring up the scan in your photo editor and copy and paste the left (or right) half of the normal stamp over the candidate. If the candidate is noticeably taller than the normal one, then you might have a rotary sheet waste stamp. There are other considerations, but if the perforations appear to be genuine it is certainly worth submitting the stamp for certification - an absolute necessity if you think your stamp might be a rare rotary sheet waste candidate.
I've taken the liberty of performing a variation of this alternative method on the image of your three 2c Hardings posted at
https://goscf.com/t/19504#171816
The vertical slice was taken from the right hand stamp that you had measured as being "22 and bit mm and 19 and a bit mm." When overlayed on the two left-hand stamp images, it appears to me that all three stamps have the same vertical dimension. Unless you're extremely lucky, they are likely all Scott 610.
Steve