Tell us about yourself!
I've done this with cedar, cypress and pine, but I use a torch and don't burn it quite as much as you seem to. I've cleaned it up with brushes (both metal and nylon), sandpaper, and steel wool. I like steel wool the best. I like to reveal the grain a little for contrast. I have finished it with tung oil and polyurethane. Both have worked well for me.
Tell us about the ladder!
This is a really interesting project. I know a little about this stuff. I have a professional EEG amp and 6 caps and have been doing this stuff for years, so I can easily try this, but this is a DIY site! I think it would serve the community more to focus on more affordable options.
The way I learned this is to fold up a little fin with the loose edge in order induce spin. Also, you can make these in a left hand or right hand configuration by changing which side you tuck on the inside (although a right-hander can throw the left hand version underhand and vice-versa).
I really like the case you used! I made something similar, but made a wood case and used a 8 x AA, 12V battery pack I found on Amazon for about $4. I filled with Eneloops, so I prefer to use the Panasonic charger.
You should try clear resin with a glow-in-the-dark powdered pigment. It's fairly inexpensive on Amazon.
I have gotten some bad connections from the solderless connectors I've tried. I think it's better just to solder them and be done with it.