As far as the ditto goes, from my experience proper use of bacon often determines the outcome, who can zone better etc, provided you are not spamming it waiting to be punished.
Personally whenever the other G&W escapes a combo or shield pressure with upb, I like to spam bacon to prevent them from coming down with a dair or just rack on some nice percent, if you feel they're at kill percent when theyre above you, you can throw out some bacon, and try to follow up with nair or fair.
If you're coming down from above something that not alot of G&W's do, but really should do regardless of match-up, is b-reverse and/or wavebunce bacon when you're right above the opponent, it catches alot of people off guard and is a much safer option then coming down with dar(which gets beat out by so many moves).
and dont edgeguard g&w with bacon, like, ever. because reasons.