Olympic Dumbbell Handles - Two Collars per Side?

I currently only have olympic plates/olympic dumbbell handles in my home gym (as far as dumbbells are concerned). I am wanting to add DB pullovers and I have what I think are pretty secure collars (Amazon genuine lockjaws and CAP spring collars, which I’ve tested both on my Barbells with 135 lbs vertical and passed). But there’s always the off-chance that they lose their grip or malfunction, or whatever, so I’m wondering if attaching both to each side will result in the combined gripping power of both or if I’m just really bad at physics? I realize with the DB vertical the collars will take the full force of the plates and wondering about safety or if I should just bite the bullet and invest in some spinlocks?

I think it’s gonna get weird. You can do pullovers with a bar or even grasping the DB collars

I’d just wrap a miniband around it (twice, so I makes an X, crossing over the handle) as a failsafe.

I’ve had spring collars slide off doing DB rows, not sure I’d trust them with any substantial weight over my face.

Agreed . I will only use fixed dumbbells now especially for overhead work.