Is it better to get MBlade E1 or Save for Acheron's E1 and E2?

Good morning, guys, my doubt is about if i should try to pull for Mblade E1 or save for her E1 and E2, i'm a Acheron enjoyer and plan to vertically invest at her team, i'm currently using My E0S1 Acheron with MBlade E0S0, SW E1S0 and Hyacine E0S1, i have Welt E1 at the moment and i'm a F2P player, is the E1 of blade a really worth improvement? or should i wait and save for Acheron's E1 and E2, if u guys have also any sugestion for my team, i would appreciate too, i think my SW E1 is better than an E1 Welt, right? also, which character now would be the best third in slot unit for a E0 Acheron, a E4 Welt or a E2 SW?
Cheers