The Mega Dolly Llama is a deadly pattern for both kings and silvers.  With that being said, the Mega is a 1/2" longer and uses the largest conehead produced. This means that it is harder to cast and can be a arm/should destroyer after long fishing sessions.  We recommend sticking with the #2 for silvers unless you need the added weight for getting the fly deeper.

We hope that this is insightful.

-Alaska Fly Fishing Goods