I'm sure it's all already documented but yea G&W is pretty awesome at tech chasing, it's not often discussed since he doesn't have a lot of moves that commonly put characters into tech chase situations (like Sheik and Falcon do)
All of his Aerials are amazing for tech chasing on platforms or on the ground since they last to long and cover so much area. Combine that with G&W's fast air, medium ground speed, and great wave dash....it makes him able to cover many options. SH and FH Fair are my bread and butter since it's so massive, comes out rather fast, and can cover most escapes.
Throws on top platforms to waveland re-grabs or jab resets (as of course any aerial, *NAIR* especially). FH bair, Dair and Uair can lead into re-grab or combos.
In general his jab is a great reset tool since he's mobile enough to follow up with wavedash or just air/ground speed.
Something unique that I like to do is cover techs and limit options with sausage. When they are in hitstun or teching from a throw/attack, instead of doing a traditional predictable follow up attack put out a wall of sausage where they are (or are going to be) and then go in for an attack/grab as the sausage hit confirms (or forces them to block). Almost always catches them off guard and leads to better combos or even a KO. If you are observent enough you can use the sausage to set up a hammer.