Having just picked up my grail pen, I was astounded by its size and thought a post such as this would be a useful reference.
Take a look at the comparisons with a green Dinkie 540 (c.1950) and with its larger counterparts, a #77 (c.1958) , #58 (Red Herringbone c.1958 & Silver hatch c.1955) as well as with the c.1940s flat topped #1200 and the mighty Onoto Magna Classic (2019).
The heart-breather nib design suggests my pen is a first edition. The #100 was released to coincide with the Golden Jubilee of Conway Stewart in 1955. Later models featured one band, no bands and a Duro point with a circular breather hole, like the #77 and the Herringbone #58 you see here.
Please add to this post with your own comparisons, if not for the sake of usefulness then do it for the eye-candy!
Edited by WhiteStarPens, 09 September 2020 - 14:51.