With 42" high cabinets and a 108" ceiling, that's 12" of crown molding if the cabinets went to the ceiling.
With 120", you have 66" to work with. I think you need 39" tall cabinets with 18" above and 9" of molding. The ideal proportion for a stack is 2/3 and 1/3, which is very close to 39"/18". Also, you really want more molding than 6". If you want 12" of molding like at your last home, then do 36"/18".
Also, if you are doing a true stack, separate the uppers from the lowers by a simple bead molding to help with the inevitable seam. It's a great look. Be sure to ask about the warranty for extra tall cabinets if that is what is being done instead of a true stack. Longer wood is more prone to warpage. Some cabinet companies will make extra tall cabinets, but not warrant them.
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Countertop ideas
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