not sure about the vinaigrette it should be 3 parts oil to 1 part vinegar .... so if you have 1 tbsp worth it would be approx 2tsp of oil ..... sorry esource is down so i cant help any more then that at the moment
I always thought it was the other way round most recipes say 1 part oil to 3 parts vinegar , also check to see if it has any honey or other sweetener in to balance the flavour