Hello Doug,
I too would lower the pressure plates to the ground using a wire coat hangar or thin rope. This is easier if your cabin keel inspection caps are removed. You should label all keel bolts and plates and return them from whence they came. Paper F has some great advice, and is available to members free of charge in the Reference section of this website.
When the plates and bolts are all out on a bench, I recommend you check the doublers for wear and confirm that the bolt D Sections lock into them OK, and do not slip past. If in doubt, please upload some photos. See photo below, noting one doubler is set back and the other in the photo is not. Also it’s worth checking and perhaps re-painting the keel boxes behind the pressure plates. The second photo below shows one of Martin Bennett’s keel bolts which he has milled grease channels into, to allow better grease penetration. Good luck.
