You are a very rare exception, who
has the ability and patience to play 8 deck and your play depends on a ton of variables. As you noted, "1.5 cutoff at worst, and S17,DS,LS", may make the game playable, but are hard to find.
But some other issues which make 8 decks almost impossible to play. Such as, the tables have to be empty enough that you can get a seat when you find this type of table with a good count, if you wong out on bad counts you may not be able to get back in the game at all, alot of shoes never get to that great count, if you set thru the poor or bad counts so that you can keep your seat, the cost of all those flat bets makes the game almost unbeatable, if you do get a cut of 1.5 (very rare today)even great counters occasionally get disturbed and lose count due to the large number of hands dealt in 8 deck resulting in more wasted time, if you are setting thru most shoes to get a playable advantage requires a large increase in bets to make up for all the flat bets and makes you more subject bad variance, the other players and pit may get intolerant of you jumping in and out a game, if the casino is busy it can take an hour or two or even more to get a shoe that justify increasing your bet. If you play when the casino is slow you are more likely to be notices by the casino personnel, which requires keeping you playable sessions short. And this is only a few of the problems with 8 decks.
Team play may help, but still requires that a empty seat(s) is available at the right time, plus a lot of stand around trying to not be noticed by the wrong people. If you play at the same casino on a regular basis, team play, jumping bets and wonging becomes risker.
In summary, to play 8 deck with an advantage requires alot of patience and wasted nights.
But I rather discuss 8 deck than 6:5 blackjack. Can you believe even on the GC pages some people are discussing theories on how to play 6:5 games? As I said no matter how bad the game gets some people will claim they can play it and at least play even.