Right then, I just wanted to share this little trick from my biceps to help make it easier for others regarding making false return edges. The CRL picture shows what looks to be almost no return edges on the bottom of the bicep and a return edge on top - PLEASE NOTE - There is no written requirement for return edges on the bicep. I have seen other builds with and without return edges so I draw the conclusion that this is a personal preference (possibly due to variation in armor molds).
Take your first trimmed bicep and lay it over the other, trace it while holding the two together tightly. Presto! Line transfer for easy cutting.