I would hold back a male spider and 2 female normals. You then breed the male to both females and increase your chances for spider clowns.
For my spider albino to pied pairing, I also got 7 eggs. I kept 1.1 normal and a 0.1 spider.
In your case, you'd keep a male spider to get more spider clowns, whereas I kept a female spider, as I'm not interested in a spider pied, though I would keep an albino spider pied.