I've been watching the Next Generation for a while but on my dad's recommendation I started SNW and I love it. I'm getting through it really quickly and thought about jumping straight to TOS after.
Is it going to be really jarring or do the two sync quite nicely? Do the characters feel a bit flat after all the exploration they get in SNW?
That would be an interesting way to do it. I think you have to do it, just to report on it for the rest of us.
Just be aware that tv shows in the 60s were not big budget affairs, and tos has campiness.
That's okay, I love Twilight Zone so I don't think it'll be too bad.