from what you've told me you have an edge
with basic strategy if the game is otherwise a typcial United States game.
6deck, S17, DAS, insurance available, and full early surrender (against any card, not just aces/10's) will give you an edge of .048% as per www.qfit.com/calc.htm, the basic stategy advantage calculator you can find at Norm W.'s site. To that add the adjustment for doubling on an ace, .1%. And you say you can spread 1-20...it seems that you should be playing and not worrying about your edge.
The special bonuses you mention add little to your edge, and you should not vary your strategy to take advantage of them. They will rarely occur and I don't recall their value (I believe Pro Blackjack or Basic Blackjack by SWong gives their value)...my guess is that the edge from those is only .01%.
Caution, you may need to adjust the estimate if the rules are different from what I understood. H17 is typically worth .18-.21%. The early surrender rule is often limited to ace only or 10 only, and that would take away most of your advantage. Also, does the dealer take a hole card after all the players have played their hand? If so, that will also take away your edge (I don't recall the precise penalty for that).
Your game sounds a little too good to me. I don't think anything like it is in the United States (if so, it would not last long as counters would burn it down quick), and that your game is in Asia or Europe, thus may be some other items I have overlooked. Or, is it a continuously shuffled game, or an internet game? Counting will help very little with these games.
But, with 80% penetration and 1-20 spread as you have stated earlier, you can beat that game with a level one system such as Hi-Lo Lite or Red 7, even if the house has an off the top edge of .6% over you.
