Consider using a Wichard 6504 folding pad eye for your lifeline
harness attachment point on the cabin top. This pad eye uses three 1/
4-20 UNC machine screws and is rated at 4410 lbs safe working load
(SWL). Look on p.827 of the WEST Marine 1999 Master Catalog.
A nominal 1/4-inch ID stainless steel fender washer has an OD of 1
inch. Three of these 1 inch OD fender washers should provide more
than enough backing plate area to withstand the pad eye's SWL on top
of the cabin in the area port and starboard of the companionway.
The folding padeye will be much less of a line snagger and toe
stubber than a fixed pad eye.