Zoics are great shorts, but I see what you mean: I'm still using the padded liner from my Zoic Vim from 2000 in my unlined full-leg running tights, but my newish Canari Exo shorts have like twice the padding.
You're pretty brave: Tackling the century with your longest ride being 50M. I give you a lot of credit for having that much faith in yourself.
Pardon me, but did you say "body armor drinks"? Pray tell. What are they?