Checking for lenght is easy once you have a adjustable push rod and at least one light checking spring, so do not be shy of doing it yourself if need be once you have looked on line as to how it's done.
Just because you could toss it together and it will run without noise, you will not be getting everything you expect out of the motor, and most times custom lenght push Rods are no more then a 12 day wait time.