Thanks for the responses so far,
I guess I could go with the 7u or I think erica synths has a similar 6u case, I like the affordability of the mantis - I know it sounds silly but space and size are concerns for me along with having a flat (parallel bottom/sides)
I guess I'm also trying to understand why I would want to go bigger if my goal is to have a reasonably simple single voiced synth with effects - even in the 104 4u case I could add more utility and another oscillator and that would be nice but its kind of surpassing what I want to achieve.. not doubting you guys know and have experience with this, just failing to see where the line is/what I'm missing to hit my needs - or is the bigger case thing just a room to grow into thing because people are never happy with what they have?
an expression pedal interface is actually a good call, remember seeing a red one whilst looking at this, in terms of the env. & pitch followers.. I think I would try do that with a midi pickup rather than tracking - i had looked at the mutable inst. ears and disting mk4 - although the disting mk4 seems like a great module to have regardless so i might add it to the list anyway, that way it probably wont go to waste if I don't like the tracking.
Anyway thanks for replying hope I don't come off as ignorant about the case size