Harry,
Love your first Pens congratulations. See you are having fun with design as well, I agree straight line Slims are not for me either. The Streamline kit has a fatter centre band and I continue to make Slimlines after more than 15 yrs and bulk buy Sreamline Centre Bands and use them. I personally make a variety of Slims out of Rebar, Dart Bodies, Beads etc but mostly using Aussie Burls.
In all the years of making Pens no one has ever said why dont you do them without that Centre Band this I have only seen on forums by some makers who have this preference I make my pens for people mostly even now have never seen a wood pen, this is my hobby not my profession.
I agree on size of picture, kept within the frame is best, sharpness can be maintained by keeping the pen parrallel to the camera, all of these considerations become clear as you move forward.
Once again your pens knock the socks off most beginning pens I have seen. I finished school at age 15 your age 61yrs ago and making pens is addictive and fun and I trust you continue to enjoy having fun with Pens.
Regards Peter.