Hood Scoop time. ???s

My 73 scamp now has a new Trick Flow intake that is too tall for a stock hood. The air cleaner bolt has marked a nice centering point for the beginning of the hole. My question is, If I have a 14 inch air filter, how big should the hole be to allow for closing the hood and for engine movement under power surge? Is 1/2 inch clearance appropriate, 3/4 inch? I will be putting a scoop on over the winter. Also, it appears to me that the hole will be offset to the passenger side by about and inch. Does that sound about right? Any advice on how to undertake the process of measuring, cutting and finishing the hole would be appreciated. Thanks8B938DA4-A29E-4B92-9A1A-29943CFAB6B7_1_105_c.jpeg