Yes, my bridge plates on 12's are quite large, but then I also use a different style of bracing on them. Here's a comparison of my 6 and 12 bridge plates.
My tops are also quite thick, but I use .070"-.014" strings on 12's.
I've not seen the Antes print, but you just can't make a blanket statement like they are overbuilt. A 12 string is a completely different animal from a 6. Depends on the strings you want to use, the tone you are looking for, and how you are going to tune them. If you want a "harpy" sounding 12, lightly built and extra lites might work, but if you are looking for a fat tone, heavy strings and an "overbuilt" box with a long scale tuned down to C+ or B is the way to go. Remember you have twice as many strings that drive the top, so there is a lot of power there.
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