How much blood from the entrance/wound area shouldbe expected 24 hours after stereotatic brain biopsy (ct immediately after was clear)?

Very little. Stereotactic brain biopsy wounds are typically small in size and hence may ooze several drops of blood. If you are having large amounts of bleeding from your wound, please consult your neurosurgeon.
Small amount. A small amount of blood on the scalp is common. About the size of a quarter is frequently seen. If you are concerned ask your surgeon to take a look.