First of all, congratulations on your GL. I had set out to buy a Steinway. I was going to make the sacrifice. I decided to play as many pianos as possible, many of them not knowing the brand or model. My favorite two were the Shigeru Kawai and the GL40. I liked the GL40 so much that I ended up choosing it over the Shigeru as well. I like both of them, but the GL won me over and in the process saved me 10s of thousands of dollars. You got a world class instrument there. Enjoy it.
I just keep track of humidity levels in the house, make sure it’s not above 60%. I absolutely love the piano. I just had it tuned for the first time since purchase. It sounds amazing. Voicing on this piano is exceptional.