I'm afraid I am not very knowledgable about Stuart tadpole lampshades, but I have always admired the shades in the old King's Theatre in Edinburgh, which I believe to be Stuart.
And they're just like this.

Not all the tadpoles are the same colour in the theatre - where there are an abundance of these fabulous old shades. I suspect they may have had to replace some over the years and were unable to obtain an exact match, but I don't know for sure.
I have tried to track down an image - unfortunately all the shades are lit, so difficult to see. In image 5, when you blow it up, you can see the general shape. (I don't know which image will appear for you.)
https://www.historictheatrephotos.com/Theatre/Kings-Edinburgh.aspxeta. I've just checked the link. The image that shows the shades shape on enlargement is called
"Auditorium from stage".
I have tried to find out more about the shades in the theatre, but nobody knows much. The theatre itself is 112 years old and has some amazing stained glass everywhere, I believe the shades are original and have been kept even throughout a few refurbishments.
The shades were there 50 years ago. I can personally vouch for that.

My brother thinks they're Stuart, I think they're Stuart. We have checked them again, fairly recently.

What else could they be, in an Edinburgh theatre that old?
eta again. I've been searching and searching the web for another image of your shade and cannot find a single one.
The only ones I have seen, are the ones in the King's Theatre.

They are two-coloured tadpoles on the shades there. The outer colour is amber, but the internal dot is either red or green. (I can't remember if some might have a yellow/amber or a blue dot.)