just took a quick look at your link above Loren to your installation... seems to me quite shocking the builders would use two bolt bases for the main cleats on a boat that large. Nowhere near substantial.
Our boat displaces 10.6K, and the published displacement for the 35-2 is closer to 12K. So while there is certainly a point of diminishing return when spec-ing out these parts, I suspect that our factory aluminum backing plates, under the deck layup that they used was sufficient. Probably.
As pictured in my blog, I did upsize the new G10 backers just to add some bearing area. I had no doubt about the OEM stuff, but did want the whole assembly to better match up with the sizing of the 10" cleat base.
I do not want to make light of your comment, like saying that one person's shock is another person's meh.... because it's really more of the bell-shaped-curve of stresses. And we all want to do what lets us sleep OK when at anchor.
Also, if you look at production boats from the late 60's to a decade later, and then to another decade later, EY was always gearing up their boats better than any the "lower end" builders. That said, everyone was continually improving their standards. Well, everyone except some builders of really cheap-a__ boats, who shall not be named here.
Heck, about 15 years ago we had an old - late 60's- Coronado 25 in our moorage that had one of its original pot metal cleats broken right off due to a large wake rolling thru -- and no other boats were affected.
More anecdotal tales.... there is a 40-something racer/cruiser sloop that used to moor down the road from me that was cruising and racing down in Mexico a decade ago. and had an aft turning block tear right up and out of the deck. Block, riser, deck, backing plate.... and all! Left about a square foot hole in the deck.
No one was in the bight of the sheet, so no injuries. With enough force, anything can give way.
So, strictly IMHO, we all just engineer our boats for the last 5% of stress, or 3%, or 2%, or.............
Like my model, yours was designed & built for racing in the open ocean, 24/7. Good starting point for any upgrades that give you even more confidence.
Sidebar: I wish we were not separated by geography, pandemics , and the cost of air travel, 'cause I would love to see your boat.
Coincidence: our previous boat was built in St Catherines.
Cheers,
Loren