First up, if you're trying to build a proper two-voice setup, you need to be thinking NOW about a larger case. The build you're showing isn't close to this, and it only has 19 hp total for your utility modules, etc even at this stage. Also, I'm not aware of anything that's 2 x 62 hp. There are 62 hp Palettes from Intellijel, but they have a 3U and a tile row, and 4ms has one, but it's a single row. Either way, though, this isn't sufficient.
Also, in order to get a PROPER two-voice setup, you're looking at FOUR oscillators...not two. You need two VCOs per voice to do things like detuning, VCO sync, etc etc...things that beef up the sound from square 1 before you even get to the VCFs. Yeah, plural...unless you're thinking of two-voice paraphonic, where you can feed your two pitches through a single VCF. There's a lot of synths that DO do this, but real duophony requires separate VCFs for each voice.
Yes, I know you see a lot of these tiny builds on YouTube right now. They're NOT typical of what's considered a proper modular, though...they're more "bespoke" tiny systems designed by and for ONE person's use, and for anyone else, they're a wrong move...especially when starting to work with modular synthesis, because you'll be forced by the limitations of someone else, and though THEY might feel comfortable in that sort of build, the odds are that anyone else would NOT be.