The above measurements were what I measured using an actual meter. Here's the ideal data:
The SB-220 Plate Meter, SB-220 Multi-Meter, and SB-200 Meter are the same meter movements: 1400 ohms, 200 uA meters. 1400 ohms x 200 uA = 280 mV.
The HM-102 HF Wattmeter and HM-2102 VHF Wattmeter are the same meter movements: 1000 ohms, 100uA meters. 1000 ohms x 100 uA = 100 mV.