Im not a fan of the tang sights, they have a conflict with where my thumb thinks its supposed to be when handling and shooting. They would be fine if your shooting habits dont include having your thumb on top of the stock I suppose. They are good sights in the strictly shooting sense.
I wouldnt let lack of holes hold me up in any way on a receiver sight, Ive done several, its not rocket surgery by any means. Receiver sights used to come with instructions for the home handy person to install them before it was factory standard. If doing a Miroku made gun, reverse the tap about every 1/4 turn to break the chip, otherwise the rather tough material they are made of can break the tap and its a bugger to get a broken tap out of a partially tapped hole.