Radii should be the same in order to simplify wheel dressing and minimize tool changes. Hole depth to diameter aspect ratio should be minimized. This is for the same reasons that bored holes are not too deep. Avoiding length to diameter ratios of more than six is a good practice. If possible, blind holes should be avoided.
Blind holes restrict the flow of coolant.
Circumferential interruptions should be avoided. Even axial interruptions should be avoided. An option to consider is a hardened and ground liner. This option must be weighed against the tolerance build up and extra logistics involved. Adequate access for coolant flow should be provided.