You really can’t make good macarons without using a scale. You can get a good one from Macys (Martha Stewart brand) that has both grams and ounces, I use that particular one all the time and it is very accurate.

The reason when baking such delicate things as macarons is that your confectioner’s sugar (for example) may have settled and one cup will have a different weight from one day to the next. Just a few grams/ounces will throw off the recipe entirely. Same thing goes for the almond flour, and for the egg whites. 3 egg whites will weigh slightly different from one batch of eggs to the next as chickens are not machines and don’t lay eggs that are exactly the same from one day to the next.

You can freeze them if using the Italian Meringue method, and they can be frozen for a few days prior. With Italian Meringue, you can fill them a few days before serving, with French Meringue a day before is sufficient but I’ve never had success freezing French Meringue based macarons.

Good luck!