I think Pit's chain grabbing is very effective. It is half of my strategy. And when you get good at it, you can predict what they will do, adjust for it, and re grab them again. If you look at some of my matches and my compilation vid, I think I use chain grabbing effectively. Grabbing imo makes you in control of the match at that point. You have the biggest advantage because it is easy to follow up with any strike easily.
Going away from the Forward chain throw, the down throw is very effect for chain grabbing also. 9 times out of 10 they will air dodge immediately after the Dthrow expecting a Uair or some aggresive attack. All you have to do is wait for them to come back down and re grab them. After they get what you are doing, you can change the throw to do mindgames because that 9/10 chance goes down with every Dthrow>wait>regrab. After a bit I do an Uthrow to Uair because it launches them high enough to get hit even with an air dodge.
One thing I like to do is chain them across the stage then down throw. Since you are at the ledge, there is going to be only one way they will DI and that is to the other end. They will most like air dodge so all you have to do is wait for them to come down and re grab them. If the damage isn't too high then you can Fthrow chain grab them back across the stage once or twice. Effective chain grabbing is all about good predictability which is easier to do with a grab than anything else imo.
One last thing, after you have chained them and feel that this throw might be the last one, a good finisher is to do Dthrow to Bair. It'll change things since you act more aggressively than the other throws.