A few questions. Maybe two?

[trivialEquinox]

Ever since I started playing Melee, I found out that sometimes I shield instead of grab while using the z-button. I'm not sure if this is a result due to my bad timing after L-Cancelling or after I hit. Would like some confirmation on this. Also I'm having some trouble ledge dashing. I main Roy, which might just be my cause. Also tried this with Marth but I still can't get this down.

 

[Pauer]

I'm not sure if this is a result due to my bad timing after L-Cancelling or after I hit. Would like some confirmation on this

Yeah, you are pressing Z slightly too early. While practicing, it helps to input Z exaggeratedly late and gradually speed it up to see exactly how fast you're allowed to be.

Also I'm having some trouble ledge dashing. I main Roy, which might just be my cause. Also tried this with Marth but I still can't get this down.

Timings between characters are slightly different, so it might be easier to do with one character or another initially, but it's all a matter of practice. Try to single out each individual step and practice them slowly on their own, like pressing away from the ledge, then moving the joystick back towards the ledge diagonally, then jump. Stuff like that. Try to practice a little bit everyday and you will soon see much improvement