i am not sure your example is apples with apples
pool and snooker have similar skills and objectives,,,ie pocket a ball /play position for the next shot
so i would not be surprised if they score close to each other playing 3 cushion.
i do not know how to predict how well the 3 cushion player would do playing pool or snooker since the 3 cushion player doesnt practice hitting the 2nd ball to a specific spot but rather to a zone
jmho
for what its worth
the first time i played on a billiard table i ran a 4
so how well a pool/snooker player would do would be based on their skill in cue ball control and knowledge of getting around the table
as an aside
it turns out this first time i was hitting balls on the billiard table with this top 3 cushion player
i was proud of my 4 so i asked him
what did he think of my 3 cushion play?
he said
"you play 3 cushion like a pool player !!!!!!"
which i took as non complimentary

it took me years to learn that he meant i had no idea (at that time) about position play in 3 cushion or that 3 cushion players played position to put the balls into favorable areas to continue their runs