Most of them are transfers from commercially-released 3D Blu-rays. There are also a few homemade conversions, such as of THE LOST WORLD: JURASSIC PARK, that I selected to be part of the collection because of how good they looked.
The reason why I plan to upscale to 4K in addition to the Inficolor 3D encoding is so that they can look good on 4K television sets.
4:3 for fullscreen versions is because those of us who grew up in the '90s are used to the aspect ratio for home video releases and television broadcasts. All fullscreen versions will be optimized for 4:3 screens; the reason why I suggested an option for decorative bars in the first place is in case I wanted to put them within 16:9 pictures with a pan-and-scan flag, which I believe would get rid of the decorative bars on 4:3 displays.
“Widescreen” implies the original aspect ratio, I believe (e.g. 1.85:1 or 2.35:1). Occasionally, a fullscreen version will be in the original aspect ratio, such as THE WIZARD OF OZ; such releases will be anywhere between 1.33:1 and 1.37:1.
I now have a Mega account, finally, so I’ll be hosting them there as space allows. If an expired release is requested, I’ll upload it somewhere else and PM the links to the requester.