I was going to use the actual height of Ross Bagdasarian Jr. (Dave IRL) as Dave's height in the series, but I haven't been able to find it.

Size chart of Chipmunks and Chipettes
Here's the size chart I was refering to earlier. I find this unreliable since all the characters aren't standing perfectly straight up like in a T-pose, especiaclly not Eleanor, but I think Theodore looks the most measurable, at 40 centimeters. From here you could use could use screenshots of Theodore next to the other characters (preferably standing as straight up as possible), to get their heights.
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