Post a pic of your kitchen work area that the cutting board will be used!
Sure a big board is cool, but really depends on your space, budget and prep habits. Here's my entire countertop, with a 17.3" x 11.4" Hasegawa—the left edge of board is only a couple inches from the sink; need the space behind board for knives/tools/ingredients, etc.; remaining space on right used for prep bowls, etc. I've comfortably used 270s and a 360 on this board—one doesn't use the entire blade length at the same time—and I'm not doing whole tuna or huge turkeys.
For me, and my space, I'd not want a much bigger board. This board also fits flat in the sink for washing.
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