Interesting ideas!
Well, the 'satanic messages' thing is a bit much, but..some artists were known to backmask lyrics on purpose, so it is interesting to try to find it.
The best way to find it is to have a tape player with reverse and adjustable speed. Anyone have a big ben or GF-9696 I can borrow to see if the crossing wires trick will work?
Everything will turn out fine, really.