CV Tools isn't a bad way to work, really. Since it's an Ableton plug in an Ableton DAW, the integration should be very easy with the ES-9.

But as for that rack...yep, go bigger. The REAL thing you want here is FX processing with what would essentially be the entire modulation section of a proper build, and that's not going to fit this "beauty case". But make sure to use this build for, as plragde notes, FX that your DAW can't exactly do with the same level of control you'll get manually with a FX build. One other change I'd recommend would be a much beefier power supply, since your build lives or dies depending on whether you get a hefty enough P/S. Always overspec the supply due to inrush currents; if your +12v rail has 1500 mA on it, you want a 2000 mA capacity on that rail. Go at least 25% higher in amperage than you appear to require, as most any circuit has a degree of inrush on power-up. It only lasts a few milliseconds, but it IS enough to pop the supply and shut down the rig in that tiny sliver of time.
-- Lugia

Oh yeah thanks for the heads up. Hadn’t realized the margins in power is probably wise.

I'm not sure if using modular as an effects rack for Ableton Live is the most prudent use. There will always be that latency round-trip between your D-A, effects and then back through the A-D converters. That's not an issue in the studio as you can compensate for latency after-the-fact.

The majority of effects you'll find in Eurorack aren't dependent on sync. You might find yourself better off with a bunch of guitar pedals and an analog mixer when it comes to cost effectiveness, bang-for-buck, and so forth.
-- Ronin1973

My impression was that latency is not much of an issue with es-9 hybrid setups. Would you mind elaborating on potential problems?

I had a mixer/pedal fx setup prior to this but found I wanted more flexibility. I’m really exited about the creativity in sending signals wherever I want :)

Thank you for the input! I think I need a bigger case :)

I'm new to the modular/eurorack world and just started building my first rack. The idea is to use it as an effect-rack for live performance. My live set is played from Ableton and sending sounds and modulation to the effects through ES-9. My question is now: what utilities/function modules do I need and benefit from? Maths/Falistri or similar? Would doing it from Cvtools or VCV take away the fun? I have a bunch of midi controllers and a Doepfer Regewerk.

Here is how the rack looks so far:
ModularGrid Rack
Also thinking about adding a Panharmonium.

Thanks in advance!