The eight stage adaptation was interesting, but not hugely compelling for the cost of nearly doubling the size of the circuit.
As for tapping into the LFO, you don't need to. You just stick four more LDRs into the same light chamber as the original. There's plenty of light to go around.
Frankly, the best bang for the buck in deepening the effect of a univibe is to put in the balancing pot that lets you adjust the dry and phase delayed signals for the deepest notches.