Well technically, having 0 at the top would be correct for a digital meter. Analog VUs have a certain amount of headroom which represents the saturation of the recording tape. All digital mixing desks are 0 at the top. There is a 'nominal' position at around -10dB to allow for peaks.

Having 0 at the top would be fine IMO.
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-- Murray I What part of 'no' don't you understand? Is it the 'N', or the 'Zero'?