I guess in a way, is just a matter of practice and getting used to each weapon and its waves (I have the habit of playing with a weapon for a while and change it so I'm always forgetting about the wave's order and stuff)
Also sometimes as I said I feel handicapped and with some weapons like the Talons overwhelmed because there're some waves that get really difficult to handle (the one with bipedal mechas and red gajas comes to mind). That's why I want to get good with the DS, because I think is a weapon that you can rely against most enemies. I think today I'll also try with the BotA (I didn't play with it or the Tonfas and Vflails yet)
I want to reach at least 3M with the Lunar too, but I find myself in a situation similar to the Talons (a lot of strategies that I used now are not that good because the essence)
Oh and regarding the green essence although I read your guide I still think that is kind of random sometimes. I have done combos of 20, 30 or 40 and got yellow essence and sometimes I do a couple of FS > ID with the Talons and got green

Usually with the DS and the Lunar I throw a lot of shurikens to make the combo count bigger so I have better chances of blue/green essence