I use lemon because that's what we're advised to use for flushing insects, including by at least one entomologist. I've no idea if that's actually been scientifically researched or just anecdotal, though, but supposedly lemon is best and it works so I haven't tried anything else to compare. It's regular "Sunlight" lemon dish soap that I use, it's not an Ultra. I'm in Canada so don't know if you have exactly the same product there. If you have earthworms in your lawn you could try flushing a small area of that to see what is the lowest concentration of "dish soap" to water that works with whatever product you can get (but don't forget to flush with plain water afterwards if you're fussy about your lawn, especially if it is hot and dry!).
