: Is there a reccomended or tried size of hardware to mount the pad eyes to the
: deck? example 10-32 or 1/4-20 screws. I plan on using finish washers on
: top and flat backing washers on the inside of the deck.

I always use the soft loops but if I were to due a hardware type I would go with the West Gougeon Bros. style of a backing wood block drilled over size with the fastner set in wet expoxy. Their book and site has info. I would think 10-24 would be plenty good. They tested a 5/8 bolt into 3" of Doug Fir tested to 9000lbs+.
Don