If you are taking photo/video, you will find postion C more comfortable and less stressful to your back.Great thread, lot of information here.
I'm pretty sure I look like picture C most of the time still. Trying like hard to look like picture B but my lower back gets sore and my glutes always seem to give up about 30 mins into the dive.
Does anyone have any tips for helping with that apart from "dive more" ?
If you are diving jacket style bc then postions A and B are more difficult to achieve. BTW, half flutter kick is as good as frog kick in ow dive as long as you are away from the bottom(a metre or so). But frog kick does has better fine control on the movement.
Ask someone to take a video on your finning and body position.