68 Dart Minitub with Offset shackles question

My car (68 Dart) is in the body shop with it's quarters cut off right now, and the wheel houses will have to be replaced anyway. I'd like to minitub the car now, but I'm not sure I want to do the 3" relocation. If I use offset shackles WITH a minitub, is there any advantage over using just offset shackles and the stock wheel well? I know the tire width will be limited by the spring location, but the minitub would have to help even with offset shackles, wouldn't it?

I apologize if this question has been covered. I tried searching and could only find questions about offset shackles without minitubbing.