My Suggestions: I think you are on the right track, but you can simplify the recipe, substitute some cheaper ingredients and you won’t know the difference. Leave out the dried Parsley…I promise you that you can’t taste it thru the other zesty spices. Leave out the basil, or add some fresh basil leaves to the salad. I’ve been making Italian dressings for years…my first cooking experience…and have come to the conclusion that dried basil is the biggest disappointment in dried, vs fresh, herbs because it is more bitter than anything. 90% of the aromatic quality disappears upon drying (as with Cilantro). Leave it out and the dressing will be better. Marjoram and oregano are very closely related (Oregano is called Wild Marjoram), but I think oregano makes a more flavorful Italian dressing. Come on, now, why would you use an Italian dressing mix in your own Italian Dressing mix recipe? It is likely that you are only tasting some red pepper from it. Finally…double the oil amount! The biggest mistake people make, in homemade dressings, is way, way too much vinegar. It should be 1/4 to 1/3 of the vinegar/oil mix…not one half of it. No wonder why it was giving you headaches!