Here is a recommended way of setting up galleries when working with private individuals, where privacy and simplicity are key.
Once you have set up a first gallery, it will be easy to reuse the same settings for other clients.
In some cases, you might want to allow your clients to download high-res files. This can be done by adding new authorizations to the access options.
Note that you can allow only specific clients, based on their email, to download the images. This has two benefits: you get a better control and view over who downloads what, and you can allow a wide group of people to purchase from the gallery (say wedding guests) while allowing a subset (e.g. groom and bride) to download high-res files for free. The drawback is that it requires your clients to create a login on your website in order to access the free downloads.
Alternatively, you can allow anybody with access to the gallery to download for free. This of course, will override any download pricing profile set for the individual images and won't provide you information on who downloads images.
Please refer to the help on authorizations for further help!