If either of those spots would expose your "condos", due to water level drops ... I'd opt for a deeper spot (or possibly shorter "limbs" in the buckets).
You also want to make sure that there's no chance of swimmers or boaters being in danger on account of those bucket condos.
Buddy of mine used to take 5gal buckets to a lake here in KY, and simply fill them with rocks & sink them ... making them basically "stumps". He caught Crappie from around them, too.
Also, if using PVC, you'll want to rough up the surface of the pipes, so that algae will attach to them.
Before you purchase any PVC, you might want to check with your local hardware stores that carry PVC or any construction or abatement companies to see if they have any they've thrown away .... (or check their dumpsters).
