Underbody advice

[ben-xzwtw]

Hi, not sure if this is the right part to post in but any help is appreciated.
I’m restoring a car and can’t decide what underbody sealant to use. Possibly stonechip? I don’t want to use something that never goes off and you get covered in the stuff when working underneath. I might also go down the route of painting the underside as well.
What have you used, what do you recommend?