Hello @ascrawa,
In the case that you might not already be aware of this, I thought I'd mention that the Westlicht PER|FORMER is offered as a DIY build only, not as a complete module from Westlicht. In addition, it is only offered as a bare PCB and faceplate - I haven't seen it sold as a complete kit anywhere (in other words, you would have to source all of your own components). I don't know if you have any previous soldering or electronics experience, but it is stated as being a project for experienced builders: the PCB appears to require a hefty amount of surface-mount soldering, which is something that I personally don't feel ready to attempt even after completing about 10 through-hole DIY module projects of my own. Of course, you can buy one built by a third-party individual, but I would be strongly hesitant to do that personally, unless the builder has proven themselves to be absolutely capable.
As far as thoughts on the rack build you've presented, I agree with a lot of what @Lugia and @JimHowell1970 have already mentioned above. Some specific suggestions/thoughts I have on it are:
- I would at least halve the number of sound sources in the rack. For one this size I would shoot for a total of four or less voices.
- Rainmaker is a huge module. I would only put it in a rack this size if you have only one or two voices that the rack is being built around, with Rainmaker being planned as a major component of one or both of those voices. Removing Rainmaker would free up a lot of room for other things (see below).
- If you go with four or less voices, and as an alternative to the PER|FORMER, I would recommend Erica Synths Black Sequencer. In my opinion, it is one of the most feature rich and user-friendly "in-rack" sequencers available for Eurorack. The firmware is still being refined, but it is already an excellent and highly capable module.
- I'd add at least one more filter. Though, it all depends on what types of voices and sounds you ultimately decide to go for.
- I would add quite a lot more dedicated modulation sources. I'm not a big fan of multi-function modules like Ornament & Crime and Disting. I find it more satisfying and usable to have a user layout designed around a specific function, rather than having a generic/minimal layout trying to cater to many possible functions. That is just my personal preference though. And it is always important to remember that you'll only be able to use a limited number of those possible functions at any given time (one, in most cases, as far as I understand).
I see those as some starting points for a revision of the rack, but certainly not a final or comprehensive set of suggestions. You'll find that there will be further refinements to make as you change things up, especially in the utility module department.
I hope you find some of that useful!
-Chace