I am wondering, without going into a dog food brand debate, which I am not interested in, what do you think is the best protein/fat ration to feed our breed as puppies and then as adults?
When do you switch off puppy and onto adult?

26/16

I think the source and quality of the protein is more important than the %. I feed puppies a 42/20 and my adults a 42/16. Puppies get switched to adult between 9-12 months. I have not had any orthopedic issues with the high protein.

I would be very Leary of 42 percent protein, leading to joint issues.

Why? I'd be more worried about high fat levels and high carbs. Protein is a good thing. Look at the amount of protein wild carnivores eat.......not too many joint problems in the big cats (for example), I don't think.

How long have you been feeding the high protein?

I've been feeding it about 3 years. I make sure that what the puppies are being fed doesn't exceed the recommended calcium/phosphorous levels and ratio.

What brand is the 42/20?

Well, I know that's the ratio on the Orijen All Breed Puppy that I've used.

The Adult All Breed is 42/16.

Could someone point me to any research that links protein percentage to joint issues? I've only seen research that links quantity of food and weight gain to joint issues. I think that the higher protein food simply have less unnecessary fillers and carbs, leading to less poop and feeding smaller quantities which might save money in the long run.

Quantity of food/weight gain does not cause joint issues. It can 'express it' and cause it to be more severe but it does not cause it.

For me, growing puppies need the calcium/phos. ratio to be balanced.. It's not the content of the protein/fat but the quality of it and to feed according to that puppy. My puppies stay on puppy food(large breed) until at least 1 yr of age before switching over to adult food.