[numbskull]

I've got some strong opinions about this plug, since I feel (rightly or wrongly) that I was at the front of their revival. And a revival is what we are talking about, since very few guys have and fish the originals.
In that, there is a problem, since all sorts of copies now exist (a situation that parallels "danny plugs") and many of those copies use the shape and lip but miss the subtleties that make the plug do its thing.
Further complicating matters, even the originals varied greatly (by as much as an ounce), and furthermore guys changed hook options to change weighting more. The end result is that there is a ton of variability in these plugs.

So there are 3 sizes, a peanut, a Jr (2.5-3oz) and a Sr (3.5-4 oz).
A good one will float level with the high point of its back just barely out of the water.
It will have a lip mounted above midline and its line tie will be just below midline (this helps get the plug deep and stable). Sometimes guys upsized the front hook on the JR model....supposedly to get it deeper. I find the Jr the most useful size. I've not fished a peanut.

I disagree that these plugs are good fast water plugs. Quite the contrary in my experience. They struggle in the canal. They have too big a wobble at speed and pull to the top. Rather, these plugs are superb deep running plugs at SLOW speeds. They will get down to 8-10 feet, then stay moving level as you slow them slightly. They tend to suspend when you pause them and most hits come when they are stopped. They do well in outflows (I suspect since my experience here is limited) because you can swim them backwards yet still hold some depth on the way out, then crawl them along the seam slow coming back in once they pop out of the flow.

They really excel fishing off jetties since, like eels, they get down and stay down where fish hunt. Another nice feature is that their low slung lip and slow level swimming motion means that if you pay attention you can bump bottom, hesitate a moment, and rise over obstructions without hanging up. You need some height (like a jetty or big rock) to fish them, however, or else you spent 3/4 of your time trying to get them back through the final 2-5 feet deep water.

By day/boat I've not done very well. Fish seem to follow them without hitting, and I've had some spectacular bass ghost up to the transom then sink away. I think this is a problem with plugs in general by day. Something deep and slow a big bass knows is not getting away from her, so she takes her time to examine it. Surface stuff is harder for the fish to investigate so if it looks helpless they'll strike.

Something else worth adding. Conrads are not the only game in town to get deep. The Musso maple and Musso Pine swim at similar depths (although maybe not as slowly). The Musso slope head is the best FAST water diving design I've found so far.