How can I pin my fabric on the ajustable mannequin with the gap in between?

It should give you something to pin to in the gap, I have not tried but imagine that using both duct tape and a bit of cardboard should give a ridged surface to pin to that should help keep your lines and seams straight. As I have not tried it I would love to know if it works for you :).

I have done this as I used to make lots of clothes. Fill it with wadding (as used for quilting). You can sew it together and you can pin it into the bottom and top of the frame.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.