I have no idea if this applies to PVT-Multi or not, I've only used it for doing initial CPL-Multi, but do some research into the term "Supervised Solo/PIC". It was designed to allow CPL students to meet the solo requirements in a twin, because of insurance restrictions on actual solo. Basically the CFI is along for the ride, but does not touch or do anything. The student logs "Supervised solo" as the sole manipulator. Might help you out.