Just a thought experiment considering that seahorses possibly spawn per monster “roll” making 2:1-9N more palatable:
2:1-9N does have a lot more mob enemies, which could lead to a higher probability of spawning the Atlantis seahorses. The recruits difference between 2:1-9N and 2:1-2/3N isn’t all that large. ( half a recruit per WE)
If the seahorses pop up at a 2% rate for any given monster, you’d have a 24.6% chance on 2:1-9N and 17.5% chance on 2:1-2N. So a 7% difference between the two levels per run, which is .023 per WE. Essentially, it’d work out to 43 WE for 1 average coin drop difference (could be 2,3,5, or 10), which would be a difference of 21.5 recruits lost on 2:1-9N.
This is just a guess assuming 2% appearance rate. Maybe it is more rare, like 0.5%? Then you’d need 143 WE to see a difference of 1 “coin drop”, which would cost 71 recruits.
Is 3 Atlantis coins or so worth 22 recruits? How about 71? So a summon would cost 33.333*71 recruits ~ 2400 recruits? I’m not really sure it’s worth it, now that I’m doing the math, tbh. I can get a Renfeld for 100 recruits in TC20 XD.
I might just stick with 2:1-2/3N.