If you put a little bit of your own touch on this, you might make a decent trick out of it. However, if you're going to go strictly by the directions you're heading into dangerous territory. For one thing, handing these to the spectator to count out will make you sick to your stomach the whole time they have them. One wrong move on their part (such as turning the deck to the side to see the backs) and you're busted.
Second, the kicker isn't a kicker at all. You're supposed to have done this amazing effect and you end with a very weak laugh at best. There's no way this makes sense.
If you want to salvage this effect, then YOU handle the cards and skip the countdown. Instead, do an instant ribbon spread and have them search for their card quickly. They won't find it, you scoop up the deck and slip it into your pocket or the case (and switch it out at the end for a normal deck if you want it examinable). The trick can end there (it's just a full-deck Princess Trick at that point). As an alternative, pull out the envelope and do that horrible "52 on 1" ending, but finish by pulling the card out of your wallet, shoe, pocket, or whatever. The unique build of the PD allows you to only have to carry a few cards on your person at a time. When they tell you the card they thought of, you just have to remember where you're holding that particular card.
Just come up with something on your own. Don't let the limitations of this deck keep you from performing some small miracle or another.