[Captainfab]

I haven't done the install you're doing, but I assume you're talking about the shackle mount for the front springs? Then yes the front bracket will locate the spring from front to rear, although doesn't that bracket have more than one hole so that adjustments can be made?

As for cutting the hole for the rear shackle mount, a hole saw will work as long as the center drill will be on the metal. Size wise I would either use what DIY recommends, the same as factory , or what size will give you just a little clearance for the DOM tube.