I have replaced all the steel fasteners in my system with brass including the circuit board standoffs and mounting screws and transformer lock down bolts, nuts and washers. This is a practice I have applied since the late 80's. thru to this day even on my new speaker build. The brass has a much lower shear velocity than steel and causes less interfering energy to the flow of electromagnetic waves. The tiny metric screws that hold the tweeter dome element to its mounting plate should also be replaced as those are closest to the moving coil and will create much interfering energy. I have not used a Derlin replacement, but that material is of very low shear as well.
This may sound shocking, but I removed the door and the mounting cover of the breaker box that is conveniently located in my audio room. With 2 friends who have listened to my system multiple times. I was able to do a quick A/B . The difference was easily apparent each time,.the steel cover was removed and replaced.
The steel is interfering with the electromagnetic field of the moving coils which varies from driver size to driver size and then to the greatest area of field disturbance the source of where it all starts the... breaker box. It would be great to replace the deep well section of the breaker box but that would need to be a custom piece of brass to bend.
I am onto to methods to maintain and enhance laminar flow with my new devices. Anywhere you put them in the music field you can retrace an individual event. It is never etched just more focused within more air. These are passive but can be further enhanced with an active device.
One other thing my new crossovers are external, and wire tied to a solid poplar board. I used some of the left-over wool felt lining of the cabinet walls to place under the inductors, thought that made sense to do.. But it was restrictive to both the bass and treble section...unstrapped them and out came the soundstage and dynamics. The engineers at Solen thought no way. I used 8gauge 49 strand Litz inductors that I then had double cryoed and dipped in an organic paint no foreign metals. These inductors have a linear inductive value to nearly 35k. Solen said their best competition was good to about 10k..These would be the best choice for at least the tweeter section...I never heard the term Linear Inductive Value before. All a part of those most important electromagnetic waves. Keep those waves linear undisturbed and focused. Tom D