@Jim: Thanks for your very helpful feedback and for sharing your experience! Seems I'm not the first to notice that working with Eurorack is time-consuming and can become addictive because it's a sea of endless possibilities ;-)
@Dave: Also thanks for your suggestions!
For now I'm thinking to swap the 903A with a 2hp VCA and a Meng Qi DPLPG because I have to watch the power consumption of the Doepfer LC1.
And yes, i can see a bigger case on the horizon (sigh).