I just sort of decided that MV3 would naturally be that, and Ellen agreed. I would also argue it's the best looking male form for Susan pictured here, but that's just me.
Speaking of Susan, I originally imagined some generic figures as examples that I could quickly draw and get the point across, but then I thought "Susan", and things escalated from there. I especially liked the idea given that some people were no doubt disappointed that Susan turned down her invite.
As a bonus, Susan has particularly long hair, so she was actually an excellent choice for showing just how much shorter the MV3 and MV5 transformations make long hair.
Incidentally, I had to remind myself exactly how tall Susan is to do this, and based on the 3D guides I use for perspective, she's normally 5' 9.56" (1.767 meters), and the MV2-5 forms make her 6' 3.53" (1.92 meters). How tall she wound up getting got me thinking, which is always dangerous, but we'll find out where that thought train took my brain in good time.