Mix 1 to 2 teaspoons of the garlic with the butter. Set-aside.
Remove 1 to 2 tablespoons fresh parsley and set aside.
In a large skillet, heat the oil until just warm over medium-low heat. Add the garlic and saute for 2 - 3 minutes or until fragrant. Do not brown.
Add the red pepper flakes (if using fresh peppers, saute them with the garlic) along with the wine. Increase the heat and allow the wine to reduce by half.
Add the clam juice or fish fumet and chicken stock, bring to a simmer and simmer for 2 - 3 minutes. Add the fresh clams, cover the pan and allow the clams to open, checking and removing the clams from the pan as they open this will keep the clams from getting "chewy". After about 10 minutes, all the clams should be open, if not, remove those that have not opened.
Add the canned clams, along with the opened clams to the pan. Add the parsley. Simmer for about 2 - 3 minutes, or until hot. Taste and add salt and freshly ground pepper, if desired. I don't find I normally need to add either as the red pepper flakes gives it heat and the clams and clam juice are naturally salty
Put the pasta into warmed bowls. Top with the clams then add the sauce over. Divide the garlic butter into each bowl along with a wedge of lemon. Top with remaining parsley and serve.