Hi Betty:
Weights aka components always take some thought. Since you have control over how much, a methodology I would think is important would include your course objectives (CO's) and Student Learning Objectives (SLO's). Also what media and related resources you have access to or need.
Next, weights. One approach is to think about which grading criteria you want to use, then assign the weights afterwards. For instance, will there be a mid-term? Final; project; homework; class exercises; quizzes; essays; group project; class participation; skills; research; these kinds of things.
Whatever is relevant, the next step would be to weigh… >>>