I would plan less (other than the mantis) buy a minimum viable synthesizer
a sound source, a sound modifier, a modulation source, a way to play and a way to listen (quad cascading vca is good for this - but will be mono only)
and then start patching it - exhaust everything you can do and you will work out what you need - then add one (or maybe 2) module at a time repeating patch until all possible patches are exhausted and repeat
NB whilst I can see why people don't like plaits so much, it's fine as part of a mix - not everything has to be phat as phuck!! - in fact it's easier to mix when this is not the case - as the thinner sound takes up less space
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities