Hi Bananagab,
Why you don't buy a Neutron next to the Model D and these two together with your computer? Might be good enough? It saves you a lot of money and efforts for Eurorack "trouble" :-)
Or if you "insist" :-) going for Eurorack, consider a bit the classical setup of VCOs, LFOs, EGs, filters and VCAs, at the very least. Here and there I see you got something already but getting at least each two of them would give you a bit more variation that you might need on the longer run.
Consider a bigger rack too and remove the Model D (and keep that in it's original housing) to save on space. You will need the additional space!
Good luck and kind regards, Garfield Modular.