I don't wean mine till 4 months as I have Jersey cows for them to suckle. At 8 weeks she'll still need baby cake, yes. A scoop twice a day sounds about right, I think that's what you're giving her? Perhaps increase it by 50% as you wean her to make up for the milk she's not getting.
At three months she can go onto 'grown up' (regular stockblend) cake, but you'd maybe want to keep her on a higher-protein cake to 4 or 5 months, especially if you have weaned early. Perhaps start mixing in the grown-up stuff till she's on all that at 18 weeksish?
I'd gauge whether you're getting it right by her condition. Too thin? More cake. Too fat? Less. Coat dull? More cake, perhaps higher protein.
There'll be licky buckets that would suit her but if she's getting cake she shouldn't need them.
BH likes them to have fresh feed-grade barley straw every day, for bedding but also because they like eating it. It keeps their digestion working well, he says. This is in addition to ad lib hay and/or silage.
Silage may have greater feed value than hay, but needs to be fresh. Also may make her squitty so introduce slowly and feed plenty of straw alongside.
(I say 'silage
may have greater feed value than hay' because it depends on the hay and the silage
)
BH just came in so this from him:
He used to rear calves on a bucket (before we had the Jerseys) and thinks 8 weeks is a bit early to wean. He used to keep them on to 3 months / 100 days at least.
Cake might not have enough minerals for a young calf without its mum's milk so he'd dose them with a mineral drench to be sure. If you can't get a single dose drench, then yes he'd get a licky bucket.
He always had them in groups of three or so. They need company of their own age.