More retriever help

[Raymond]

Use the "handles" on either side of the head while giving the "load" command.
"doubles" my guess is you are throwing two bumpers from your side? That is backyard play not real doubles. To develop marking skills, dogs have to see an object fall at a distance. Hence the word "mark" teaches the dog to develop depth perception at distances far and near.
Sit, this the only command you should use. Don't clutter your training with a broad vocabulary, sit means sit!
I will not hunt a dog or let a client hunt his dog until I am through the basic training program. That might be at 1yo or longer but, the dog will have the skills to be successful when they do hunt.
David Uriadies lives in Kinder and knows what he is doing if he still trains he may help you out.
Regards,
Raymond