MAA wins most of the time.
Duncan has a gun for ranged combat and he could shoot Webstor's grapple line or hook while his armor takes the brunt from Webs' rifle. Webs isn't as armored as MAA.
As for melee? Webstor can't use that gun close up. MAA is not only armored, but is armed with mace and short sword. Webs could use the grapple to entangle MAA, but MAA has a short sword to cut himself free. The only way it could work if Webs is lucky to entangle his arms to his body, effectively wrapping him up and leaving him helpless or if Webs wraps the line around his neck and strangles him.
The only way Webs could beat MAA is if he sniped him from the shadows. But in a straight up scrap? MAA wins most of the time.