Well skinks can help against things like DE, where the toughness of the army is generally 3 followed by few high armour saves, but against OnG, they can get crushed under superior numbers. I'd advise dropping the champion on the saurus and dropping their numbers down to around 10 or 12 per unit. I'd also go for spears at that point, since you'll be fighting generally in two ranks at all times, so the extra attacks come in handy.
I'd also drop the skink chief and go for a scar-veteran. Against OnG, you need attacks over most things. They have negligible armour values, so strength isn't necessary. The Scar Vet set-up i'd go for is one of the following:
SotSR
SoB (+1 attacks) + MS
SoB + ES
SotH + ES
SoB
SotH
Those are the set-ups that would get you the most attacks. SotSR would net you an extra 2 attacks, SoB + MS would get you an extra attack and a second magical attack. SoB + ES would get you an extra attack plus extra defence in challenges. SotH would get you ASF and extra protection (best used in challenges) and the Sob or SotH on their own are great for cheap attacks and early strikes at enemy ranks.
With leftover points, you could opt for some blowpipe skinks (the cheapest option would be to go for the SoB and get 10 or so skink skirmishers.
Another tactic is going purely for two units of 10 skink skirmishers, a unit of CoC and a mounted Scar vet. They're a powerful unit and cause fear, able to make whole OnG armies flee and crush DE units in a single charge. But they're are low on bodies.
