That said, I just realized the irony of this side bet. To break even you need to increase the chance of natural blackjack to at least 50% more than normal. By hi-low system that means at least +8 TC.
The problem is, if it's +8 TC you really shouldn't be worried about a $5 side bet when you should be betting REAL big on your main bet.
I'm looking at Hi-Opt II with ace side count as the only hope for this side bet to be realistic.
But even so, the only realistic use for this bet is a harmless cover to make the pitboss not think you're a card counter when it's profitable to make the bet.
Mea culpa! There is an error in my analysis related to generating a random shoe representation. I was removing cards from randomly selected card types rather than randomly selected cards. The initial results with that corrected suggest +EV shoes start showing up at 50% penetration and reaches about a 9% occurrence rate at 75% penetration. I'll post a corrected graph tonight. Sorry!