@John-Paul-RAGE Sylvan Wyverns Stage 31-35 is the best one for farming Meseta. (Don't forget the HP/Guts Drink for its Meseta boost bonus.)
You can get 5000 Meseta extra for clearing the HP Recovery Code on stage 31. But I never bother with it, too lazy.
Save your Julius Nifta Photon Blast (The gravity pull one.) for non-rare stage 34. Activate the blast, then immediately access the warp and basically let your Photon Blast do its thing. You probably still have to assist with killing the mobs though.
Hopefully you get the 'Falz Arms' rare stage on 34.
But even without the rare stage it's the best one.
If you are farming it in a duo, let the other person activate Julius Nifta on stage 33. Depending if that person has Julius Nifta and is able to get his/her Photon Blast ready before then. Otherwise chain your Photon Blasts on non-rare stage 34.
Oh, forgot to mention. Don't use a 250% Rare drop-boost or any Rare drop-boost during Meseta farming. You only want to use a Tri-boost and a Meseta-boost. A Rare drop-boost actually blocks Meseta from dropping.
If the quest is boosted with at least a 100% Meseta boost, you got the Khloto Mechs (Which sadly isn't in the NA version.) with Meseta Fever II & III affixed on it, make use of the Alliance/Team Tree Meseta Boost, activated a 100% Tri-boost and a 50% Meseta-boost. You can make around 6 million Meseta in 90 minutes.
(Man, I could write a guide about how to make Meseta early on in game. Sadly, just too lazy.)