Welcome Wonderof42!
If you are concerned about wasting money, do NOT put the Neutron and Subharmonicon in a eurorack case. They already have cases and power supplies attached. Don't pay extra to rack them twice. They are SEMI-modular synths, that will be fun to integrate with the rack, but it's definitely a waste of money and space to rack them twice. They're still portable and easy to incorporate as-is.
What kind of music are you making?