SDFJKL:VBJKL:
WHAT ARE YOU PEOPLE SAYING??? If you can feel the jump, the audience can hear it. I am pretty sure you do not want the audience to hear it.
There is a better fingering for thirds. You do not necessarily need to use 12, 13, 24, and 35. FOR INSTANCE you could use 23, 14, 25, and GASP 15! which I find is very comfortable to use when playing thirds. If you look at the fingering for Chopin's 3rds etude, the trill is an alternation of 14 and 25 (though I find 13 and 25 much easier) then you have 14 25 14 23 14 25 14 23, then you have a thirds chromatic scale upwards. I don't remember the fingering, but I remember it being a very good one. Look it up (Chopin etude in G#m Op.25/6).
If it's a scale, then 13 24 35 13 24 35 just wont cut it if you want it smooth. Neither will 13 24. My teacher asked me to play a third scale once, and I played it 13 24 13 24 (and I can play it like that quite fast, although not very smooth. He laughed and said he would find me a better fingering.
As for finger glissando, it really only works from a black key to an adjacent and takes an enormous amount of touch to play it smoothly. You don't want to end up accenting the white note.
Show me the score and I'll finger it for you if you want.