Skaven are strong, but they never really dominated our leagues. *shrug* They start off very strong, but personally I think other warbands narrow that gap over the course of a campaign.
Armor is generally garbage in MH just because high S and crits tend to ignore it. Max bodies and slings are where it's at for you...basically just using your movement, spamming sling shots and waiting for the crits. Use your numbers to pounce on stragglers when warranted, but don't seek a scrum.
Starting with 6 heroes is a big advantage, so definitely do that. Rout tests may be an issue for you early on, so you'll probably want to shore that up after you get some gold. A holy/unholy relic for your leader is a good place to start.
Here's what I'd run...lean and mean (free daggers not listed). You may want to double-check my numbers.
Adept, dagger, sling 64
Black Skaven, dagger, sling 44
Black Skaven, dagger, sling 44
Sorcerer, dagger, sling 49
Night Runner, club, sling 25
Night Runner, club, sling 25
3 Verminkin, club, sling 75
3 Verminkin, club, sling 75
3 Verminkin, club, sling 75
476
It's fifteen models, so you stay in the 13-15 column for wyrdstone selling. I like having a gold reserve in case the first game or two goes pear-shaped and you end up with a few deaths.