I switched to 3" pans several months ago because I could NEVER get 2-2" cakes to look the same & fit right on top of each other. I only use 2" pans when I have batter left over. I use the left over batter for cakes for my family.
I have all of the sizes but the 18". I hope I will never have to bake that size!! Toooo big!! I started buying 1 or 2 at a time. I use the money I get from cakes to go back into getting my supplies. All I need now are the other shape plates. I'm also starting to buy cake stands, pillars, fountains, etc. One day I'll have all the stuff I need to open a cake shop! That's my dream!
I use the same recipes I just double them. When I first started using the 3" pans I would measure out the batter. I used the Wilton charts for amount of batter for each pan. Now I can just eye ball it. I like to fill the pans up high enough so I can level it evenly with the top of the pan, after it's baked. I learned that from CC!! Be careful because it will run over & cause I huge mess in your oven!!! I found out the hard way
I use Magic Line pans. They are very thick & heavy. You will have to lower the temp of your oven & bake them longer. I use 325*.
I hope I didn't write toooo much!!! I hope this helps someone!!