To be pedantic, what's being outlined here is not true pre-peg. Yes, the cloth pre-impregnated with epoxy but true pre-pre has the epoxy cure halted or stalled in what's called the B-stage. As described it requires heat to finalize the cure and pressure to consolidate the fabric matrix. Room temperature cure epoxies very quickly transition through the B-stage phase.

Enjoy your new found technique!

Matt