Help beatgridding songs on RB? And the effects/looping afterwards?

Just came Serato, got a Nexus 2 setup. Arranging all my tracks in rekordbox and I'm struggling with some hip hop, Trap (EDM i.e. Flosstradamus, Bauuer) And Dubstep (Really brostep i.e. Getter, Skrillex, Ghastly, Megalodon).

They came up as 140, I know I can half it, as I did. 

My question is, wouldn't gridding it as 140 give me more flexibility in doing loops and beat FX? seeing as they're are more grids to go off of, if that makes sense? 

An example would be the song Blasé by Ty Dolla $ign and Future https://imgur.com/a/rVXQQ As you can see where my cursor is, theres a vocal part where the vocalist goes "tooooooold" But you could only really isolate it on the 128 beat grid. Very specific stuff but it seems like something I should consider the first time around on my jump over to RB

Also, which of these two would be proper beatgridding "practice"? or is such a small difference insignificant?https://imgur.com/a/CC32t

Thanks in advance!