Seaberry can be an acquired taste, so if there are several of you that like it, your berries might come in handy.

The seaberry thorns may deter people from taking those berries but may not keep them from proceeding to the other fruiting plants. If you plant them close enough for a hedge, harvest will become more difficult. It has been my experience that the plants do not like to crowd each other.

All of the males I have planted get uniformly huge and require yearly pruning.

Seaberry seedlings typically, as a group, are not as productive as clones or cuttings from named varieties. You may end up with mostly foliage, but 120 plants are going to produce some fruit.

Your math and gender ratio is fine. Wind pollination is the key, so putting all the plants in a single line will reduce the harvest also, much like a single row of corn versus a field of corn. Better to plant them in a grid, like an orchard, if fruit is the main goal.

Most of the seaberry research in this hemisphere is done in Canada. There is a fellow who has planted many seeds and has posted here in years past. Use the term seaberry, seaberries, or sea buckthorn when searching the forum or the Internet. "Seaberry buckthorn" would be an uncommon phrase.

Just out of curiosity, is a seaberry/buckthorn not a naturally sweet berry? I read that people often add sugar to the juice.

Fresh-picked ripe seaberry is tart like a lemon.

Ah, I might pass then since I already have other produce that gives me similar nutrients, and I'm not sure they grow in So Cal.
Thanks for the info!