Be aware of the actual hole size.  The ones I see listed as '3/4 inch' and '1/2 inch'  are substantially larger - they are referred to by the size of electrical conduit.  It used to be that you could buy actual sizes for tube sockets, 1/2, 3/4, 1 1/8, 1 1/4 inch at radio parts distributors, but that day seems to be gone.

Step drill bits are a good alternative for tube socket punches.

73,
Don W3FPR