Well.. if you insist on running all-skink, then I'd definately suggest putting some skrox units in there as your main infantry and even some krox specials. But going up against a beastmen bestigore unit of str 4's, minataurs, or centigores are going to be tough without some muscle and ranks. Beastmen move at a 5, so even though you can still move faster, 1" isn't a lot of breathing room. Poison shots at a hit and run, drawing them into a flank position with a steg would be good IMO. Salamanders are great against high save units.. even better against those without. Not entirely sure, but Razardons may be good here too. Since the majority of Beastmen only have 1 wound.. the more poison shots you can get on them the thinner their herds will get. Just be wary of their chariots.
Sorry for the jumbled mess, these were just some thoughts and opinions as Im winding down for the night.