Any two team hook up in my opinon is not a good bet. Teasers, parlays, reverses. That's my opinion.
Not so fast , correlations become extreme. It worked great in NHL parlaying dog +1.5 pucks and under 5.5 goals. That was a cash cow ! It would work in soccer, if you could get a taker for the bet. Many early books got their azzes handed to them by taking parlays on things that should never have been allowed to be parlayed !
Lets take a CFB game;
Team A is -40 over team B
Total is 50 points
Gee I'll parlay B +40 and under 50 at 13:5. If it goes under 50, I should win ! I can make other bets to nearly lock a profit on that. The point is that parlay should not be allowed. How does it stay under 50 without the dog +40 also covering, answer is far fewer ways than the ways and probabilities of me winning at +260. Try betting that at Pinny ! Maybe you got a dumb local that will take it ?
I've got a ton of theoretical stuff that's valid, just not bettable, or formerly bettable. I learn from the old stuff. I'll snuff any dumb local with it.