I'd advise bigger still - you have no room for expansion past what's in the 'bigger' case and imo 1u is a false economy - the cases that have it are expensive for what they are and often include superfluous functions that you may not need - midi and output modules are the main culprits here!
get a tiptop mantis instead and there will be space left over so the inevitable 2nd case is further off...
the mantis is best balance of hp/cost/manufacturer reputation/good power supply there is...
getting a tiny case 62hp and planning a 2nd 62hp cases immediately is a waste of money!
and spending a little bit more to buy a mantis will at worst set you back a month or so on buying a module - and you should go slowly buying modules anyway so that you learn them properly rather than superficially, before adding more modules...
"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