A hand mirror and a deep socket with a couple of 3/8 drive extensions might help. Position the mirror behind the seat back so you can see the nuts, then guide the socket onto the one you want to undo. With the right combination of extensions (they come in 3-inch, 6-inch and 12-inch lengths) you should be able to attach the ratchet handle at a comfortable height.
Who does the turning (the ratchet or the person on deck with the screwdriver) will depend on the condition of the sealant. If it's old, you can probably turn the head of the screw but if it's still tight, just undo the nut...but not completely. Just before the nut gets to the end of the bolt, push up hard on the ratchet to break the seal and push the screwhead up out of the jib track. If the seal is really tight, remove the ratchet and tap the end of the extension lightly with a hammer. It saves having to go back afterwards just to push the screw up. I hope that helps.
Peter
H23 "Raven"
Pearson Wanderer
