My FBO requires 3 hour dual in glass-equipped Diamond, unless you have 3 hours logged in G1000 equipped plane. That includes all necessary instructions. Check with your FBO, they may offer you training.
I can pretty much guarantee that if you go through some formal home study for the G1000, be it books, DVDs, or online, you will save money in the final training in the airplane with a CFI. With the proper ground training program, you will go to your first flight lesson with a HUGE head start. Invest a few hours in homework - it will save you money!