Excellent! The retriever should completely focus on the mark and ignore the handler. One mistake beginners make is a hand signal release..that diverts the focus of the retriever from ” burning in on the mark” to the handler. I like to teach pup to “burn in” or focus on the mark and ignore the thrower by starting stand-alones from behind the retriever. That way the retriever learns the routine is to focus on the mark until verbally released by the handler. Focus is the key to pinpoint marking. I also use stand-alones to teach pup to mark off the direction the simulated shotgun is pointed. We do this by using a radiator clamp/old rifle stock and a dummy launcher. https://www.youtube.com/watch?v=EzzDUiVeudw