Funny you should mention too tight.
I shredded my first o-ring last night recoiling the R2. Luckily the R2 came with a spare.
I think if you crank it too tight then the o-ring will pop.
I don’t think there is any issue over tightening as far as juice flow is concerned.
Check out CAPPY VAPES on YouTube. He mentions sliding the white silicon top cover over so that only half the juice fill is showing which supposedly helps with wicking somehow.