Oh yeah I forgot about that room lol, but I pretty much know roughly where the targets are, so I usually don't use the lens in there. And a little tip (for anyone who doesn't know) about the room & the spikes .. wear the hover boots and if you walk over the spikes you'll hover over them opposed...
There's also the Shadow Barrier room in the Castle with the hidden curvy walkway leading to the switch that opens the door to the last room. That wouldn't be as difficult to memorize as the Wasteland, but still would be a lot of work.
In the Shadow Temple I really only use it 3 times .. for...
There is the first main room with the invisible skulls where 1 of them shows up with the Lens, which is the one you have to push the thing to. It's random which skull it is, but I suppose it is doable with trial & error and enough life hearts.