Does anyone do recreational activities on the pond without you? A giant rock ledge just 12" below the surface might be a boat killer, dangerous to a falling paddleboarder, break the hand of a swimmer, etc.

I agree that the value of a rock ledge is that it gives you "habitat" on two sides. However, that is going to take a lot of rock! Is 70 tons enough to make 160' of ledge?

I suspect that you have very little wave erosion of the shoreline with your pond in a tree-lined valley. However, stopping wave erosion is a consideration for most pond owners. You might consider installing your rock on a few banks and running it up to just above your normal water level. That would only take a single layer of rock, and you could run it all of the way down to 6-8' below the surface where the bank slope easily allows that. Your crayfish, insects, and baitfish could then each find the depth they consider optimal. Also, your "rocked" areas will then be visible to anglers and anybody else on the pond.

Finally, every pond is different. There is a lot of value in experimenting in YOUR pond. Do part of the work in a few different niches of the pond, and then see which areas produce the best results. Copy more of that distribution of rocks the next year. (Unless of course you are renting heavy equipment for a one-time installation of your rock. In that case, probably better to minimize your costs and use the savings for other pond improvements.)

As regards your fish populations, a 35-40 year old pond has almost certainly lost nearly all of its "non-rock" cover. In addition to spawning beds, the forage fish need some dense cover for hiding, and your LMB need some different cover for their ambushes. In the satellite view it looks like you may have felled some trees into the water? If so, that is certainly a good start IMO.

Are you going to draw down the pond to install your rock ledge and spawning beds? That would be a good time to add some other types of cover as well.

Have you downloaded a relative weight chart for largemouth bass? That is one of the easiest ways to get some valuable information about the health of your bass population and by inference some info on your BG population. The lack of big bass suggests you may have too many LMB in your pond. More spawning habitat is NOT the solution to that problem.

If you keep weight and length catch records, there are some serious experts on the forum that can help analyze your population.

Congrats on your "new-ish" property and beautiful pond. I hope you enjoy creating your pond improvements, and then enjoy even more your better fishing results!