I just tried with ByteConverter and can see where the confusion is. ByteConverter will literally convert 4 consecutive bytes into a float. Whereas I assume that you want to fill the new array with the values stored in in the byte array.
You can just create a new array of the required type with the size of the original and copy the contents. The type will be taken care of.
It may be better to use type Double, see
this thread. So:
Dim DoubleArray(ByteArray.Length) As Double
For i = 0 to byteArray.Length-1
DoubleArray(i)=ByteArray(i)
Next
The stored precision will be whatever is appropriate to the number, you will need to use NumberFormat to display the required output precision.
The other thing to remember is that bytes are signed.