Ooops - before I hit the send button, I glanced to the Scott Wmk 360, Star and GOVT INDIA and it measures from point to point aprox 25mm in the book which matches what I have. So is it possible to have a Wmk 360 in which the star takes up the whole back not allowing room for any of the GOVT INDIA to show?
The Catalogue image may not be to scale.
You have to balance your opinion between discovering a variety, and seeing something that is not there.
One can easily be seduced by thinking one has "new discovery"
I am ignorant of what Stanley Gibbons considers "India Govt in sheet"
I do not know what "in sheet" means.
Perhaps other members can chip in.
If I were you, and in a learning stage, I would place the stamps in water, ID the watermarks, and measure whilst wet.
Put the whole process down to your experience.
Place your results here so we can benefit.
Notice the Large broad star has flatter "arms"