Ok, well, now we know what your up to... I say go for it.... You don't have much to lose....Just be very careful you don't get zapped!
Use your multimeter to check for the voltage after the rectifier.
Perhaps even try just a single diode so you keep the drop down to .6 rather than 1.2? (In which case you will need a cap, but since you are just measuring stuff at home and keeping the cost down.... a bit of non-linearity can be managed).
Chuck that into a DC voltage module and you will get something.
I was thinking that you were in a production / business application and bending the rules is not always a good idea there, but as you said, the CT was cheap, you are in a situation where accuracy to the nth decimal place is not critical, you will learn a bunch, so can afford to experiment a little.
Regarding the Pi, I have two of them and cant say much about what we are using them for, but enough to say its Opto related.
I'm a big Linux fan, but cant code for peanuts (and I love peanuts!), so that limits me to just hacking about with other peoples code snippet's. (Perfect example can be found here; http://www.opto22.com/community/showthread.php?t=380 )
As you say, the old B1, B2 stuff is bomb proof. Put a bunch of that stuff in the hospital when I started there in the very late 80's.
Its still there, still working to this day.
Lets know how you get on.