Yes you have to verify the action is transfered to that lever for the choke cable setup to function. It probably is as it is a mechanical system to the best of my knowledge. If tnhe engine will cold start easier with someone holding the lever you know it will work.

The base pressure does impact the reverse side of the diaphpram or whatever is impacted in the pump. Thats where the old test that is now not recommended originated.

You start the engine and plug the breather hose with your finger or whatever. Count the seconds the engine continues to run. Ten seconds is a very good indication the blowby is not excessive. Under five is not so hot.

You probably knew of this test already but others may not. Some feel it may blow out a weak engine seal. So the test is no longer recommended. Let us know if the choke cable approach looks sound and indeed works out. It should but there can be issues with everything but not allways.