how to paint a leaf spring??

[37pickupproject]

I just picked up a new leaf spring for the rear of my pickup. I got a 2 1/2 in drop spring from posies.

My question is how would you recommend painting it? Take the spring apart and paint each leaf seperately? What paint would you recommend? I don't have access to a real spray gun so it's either brush on or spray bomb for me.

Or should I skip the paint and just use a none hardening undercoating and spray the leaf spring assembled?

Thank you for your advice !