Bass will only go as deep as the thermocline allows. Even though fish will travel into the colder lower layer of water, they can't stay there, or fish suffocate.
Remember this..90% of fish live in 10% of the lake. Pick your areas, then put in cover. The HOA shouldn't object to improving the lake.
What's the best material to use? Depends what you have. I like limbs from hardwood trees, especially limbs 3-4" diameter, tied together and anchored with a concrete block. PVC pipe works well, drilled with holes, with smaller pieces of pipe pushed through. Make an artificial "tree" of PVC, and put several trees in each area. Rock, concrete blocks piled like a pyramid work well, too.
Think like the fish you are trying to attract. Bass like "fluffy" cover, sunfish and other forage fish like "dense" cover. Peripheral is best, but big shallow flats will hold fish, especially if you create a pathway to and from the shoreline to your main cover. Bass and bluegill don't necessarily appreciate having to traverse distances where there's no cover.
