The first thing about why the Fo-Felix is more effective is the resistors that bypass the coils. Independent people have confirmed that they are a sonic improvement, on top of the objective reason which is to stop electrical resonances with the CMC, from the diversity on the AC lines.
As stated in the other thread, the problem with using multiple capacitor values is they can start talking to each other, and when they resonate with each other it's hard to predict just how far those effects may be audible; but they could go from nearly benign to fatigue. The negative consequence does not out weigh the (small) benefits of varying sizes.
They can be arranged any way you want. But if you mean ran in series, it is possible. But I'm not condoning that because it isn't an ideal circuit. It creates the same circumstance of having capacitors following the CMC, which does not appear to be optimal in results.
The reasons why I've done the different changes is from years of development working with CMCs. When you really start digging you find out very quickly that trying to squeeze the numbers for the highest/ideal attenuation is pointless when you ruin the sound at the same time. It looks like you're making a compromise, but when you hear what a filter sounds like without simultaneously butchering the complex impedance, you quickly know that it's way better. You're really getting the benefit of my R&D, that has been on going for some time now.
I'm trying to think of a good analogy... The goals are to create a stable improvement that doesn't have negative consequences, as opposed to stacking improvements on one side of a teeter-totter while the problems shoot up on the other. It's important to understand that the AC mains are very complex electrically, so what you think you know may not be true. The reality of the original Felix is that it was merely OK. Some of the results may have been negative from an engineering perspective, but were significant enough sonically that people enjoyed the difference in sound.
I'll post a graph or such in a bit.