Hey! A few questions / points to help:
- Please provide a link to your rack, rather than just the jpg, that way we can explore it more easily.
- Do you already own the case/modules, or is this all still in the planning phase?
- What type of sounds/music are you aiming to make (aka, what do you mean by "experiment with textures")?
- How interactive do you want the rack to be? Do you want it to be more playable and responsive to commands, or more generative and "suggestable," rather than directly controllable?
To your specific question, no, I do not think you have too many modulation sources; on the contrary, I would certainly suggest more. Something like a cv controllable LFO for example (for ever-changing modulation in addition to what Maths and Zadar can do - free them up for different uses). The longer I spend with modular synths, the more I realize that modulators and utilities are really what make the systems interesting. Sure, oscillators and filters and effects are fun, but any synth can do that, you don't need to dig into modular for those features. But if you want to have control over the fiddly cv details, want to be able to set up (and maybe make hands-free) changing parameters over time, or really explore unique methods of sound creation (for example, have you ever tried using the Zadar as an oscilator, or the Rene as a modulator, or the Maths as a filter - or anything really), well that's where modular shines. And for that, you should spend some more time looking at modulators and utilities. In general, I'd rather fewer sounds sources and more utilities/modulators than the other way around. What you have is a good start, but I'd think about how much space you're dedicating to effects and whether that will get you the synthesizer experience you're looking for.
You should update with a link and let us know how much of your rack is planned vs. already owned, and we can suggest further. Good luck with your sounds explorations!