I would start with a high quality puppy kibble and slowly introduce a RAW diet after at least a year.
I've had my GSP on just about every quality food you could imagine , including a RAW diet.
In the off season he's feed straight kibble , during the hunting season (Sept-Feb) he's feed kibble supplemented with basically anything we have for supper that night ie , meats, fish, rice, etc ..
For 6 months of the year he's expected to run and hunt hard 3 to 4 days of the week.
Usally around Oct he's transformed into a lean mean hunting machine.
Why have you picked a RAW diet?