Just did it recently for a LR-45 SIC type at the Seattle FSDO. Had to make an appointment. You can do the paper 8710 but they preferred IACRA. I did it all on IACRA and it was pretty simple. Had to show the inspector my logbook and some company specific paperwork that showed I had completed ground and flight training on the aircraft. The aircraft PIC signs into IACRA as Recommending Instructor to sign.
I don’t think you need an ATP or a CFI to be the recommending instructor. Just a PIC type.