Is the Danish Gambit viable for Class D tournament play? I've been recently playing the Danish Gambit online in blitz. It started as a dare from one of my friends, but I've had ludicrous success with it due to  common mistakes from my opponents. 

Also, I don't mean the wimp-out Danish Gambit with 4. Nxc3. I mean this Danish Gambit: 

 [FEN " "]
1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2


It's been doing so much better online for me that I may want to try it in tournament play. 

However, I'm worried that the slower time control will cause my opponents to make better calculations. 

I'm currently a Class D (1200-1399) player. 

So, my big question is: 

Is the Danish Gambit viable at longer (tournament-length) time controls for a Class D player?

If you don't think so, can you give me some similar openings to try out (for White) that may perform better?
My old chess tutor answered a similar question of mine quite decisively: "Just don't worry about it: Below 2000 (FIDE) you can succeed with every opening."

Lower rated (or non-prepared) players do not know how to punish the weaknesses an opening like the Danish Gambit opens - and they make mistakes. Lots of them. Playing against as sharp of an opening as the DG requires your opponent to make really precise moves and prompts them to make even more mistakes on which you can capitalize on.

To conclude: I think you are perfectly fine playing the Danish Gambit in Class D tournament chess, as your opponents are not likely to know the theory and will probably blunder sooner or later, especially if the opening fits your style. Even in longer time controls. (Also playing sharp openings is just a lot of fun!)

Another opening that comes to mind is the Grob (1.g4). It is no less dubious at master-level, but if you put the effort into it and learn some theory behind it, you can absolutely obliterate a careless player.

Finally a word of warning: The higher you rise in the chess rankings (approaching 1800+), the harder it will get to win with "one-trick-pony" tactics. So put some time aside to improve your general Chess, not just one opening.