Go with your gut. With my writing style, it would be weird (for me) to re-describe/introduce my characters each story. I like to rely on personalities to define my characters, since it's more natural for me to casually mention my computer genius sitting at his station working than say "Nick, the team's computer expert" fifteen times a story.
If you can make the reintroductions work, do it. Readers like multiple volumes. If not, try posting all the work under one link. I use different thumbnails for each story so readers can see exactly how many chapters I have per story, instead of making them assume all 120 chapters are one story.