What I understand:
When we say we're getting "30 volts AC" out of a transfomer, we mean "RMS." This is what a multimeter will read/display. This is
exactly the same thing as getting 30*1.414 = 42.42 volts "peak to peak," meaning the AC waveform peaks at 42.42V, 60 times per second (if your mains is at 60Hz.) Just like a normal 110V wall socket is at 155.54V peak to peak.
How much more voltage a transformer gives over it's rated voltage when it's not loaded has nothing to do with the above. It might give about 40% more, or 29% more, or only a few percent more. It might even by freaky coincidence give right about 41.4% more, making it appear like it's some RMS vs. peak-to-peak issue, but that would be a
freaky coincidence and
not a RMS vs. peak-to-peak issue.
Furthermore, a capacitor bank receives the "pulsing DC" waveform from the rectifier bridge and
squashes it down to its RMS value. This means that the current flowing out of your capacitor bank ideally
no longer has a peak-to-peak value. The 1.414 factor is then irrelevant. That's
Direct Current. This action by the capacitors is called "smoothing" or "filtering" and is why it's called a "filter bank." The secondary function of the filter bank is to act as a resevoir of electrons so that current demands from the load can be supplied quickly. This is because capacitors can give up their charge, hence supplying current, faster than a transformer/rectifier can supply current. This does
not affect the voltage at which this is all occuring.
Again, this is merely what I understand. As I have no formal electronics training and little experience, I defer to most anyone who does, provided the constraints of logic appear to be in play
Peace,
Sanaka