There are a lot of different types of glue ons from regular aluminums to poly flex, so weight will vary. They are lighter than steel.
I have a horse that lives in glue ons-namely polyflex. He’s a TB who just doesn’t grow enough wall up front to nail on. Standard aluminums were fine, but we found after almost a year in them they were causing his heels to contract, so we swapped to PF. I will never go back, he will be in those or barefoot. It’s a night and day difference in his entire body.
We get 5-6 weeks out of PF and the only thing I hate about them is they are slick, so he is studded on grass anytime we jump when normally I’d only stud for XC.