What is the cable pull of Tiagra 4700 10 speed? What is the actuation ratio?
According to this YouTube video, you can combine:


Shimano Tiagra 4700 shifters
Shimano GRX 812 11 speed rear derailleur
11-34t 10 speed cassette


This implies that a Tiagra 4700 rear derailleur has the same actuation ratio as Shimano 11 speed road rear derailleurs, as suggested by Argenti Apparatus. This is a ratio of 1.4. 3

Plugging these numbers into the equation we get: 

Cable pull * Derailleur shift ratio = Cog pitch
Cable pull * 1.4 = 3.95
Cable pull = 3.95 / 1.4
Cable pull ≈ 2.82


So, to answer the question: 


Tiagra 4700 10 speed shifters have a cable pull of 2.82
Tiagra 4700 rear derailleurs have an actuation ratio of 1.4