pretty sure client variables are always stored in the brick group of whoever is hosting the build, or it may be flipped and it's the client's brick group with the host's number
in my case though, i clicked a brick that set client variable duck to 5, and then ran this
$c = findClientByName("phflack"); //returned 11237
echo($c.brickGroup.varGroup.valueClient_11237_duck); //printed 5
found it pretty easily with $c.dump();, $c.brickGroup.dump();, and $c.brickGroup.varGroup.dump();
i'd recommend testing with multiple people to see if all variables are on one brick group (which i kind of remember it being that way)