You can get bottle racks for 4 bottles at the same time, and there is not much time saving to be made by having a bucket with teats (which also needs to be washed out daily).
If you are using milk powder anyway, you can either make up batches for the whole day and then warm the bottles, or make up double strength and then dilute with boiling water just before feeding time (though not with all powders, some stay more clumpy if made up stronger).
And as said above, knowing how much individual lambs drink is always useful. I also find not ever feeding more than 500ml in a single feed just reduces the chances of bloat so much.