Nice work, looks good. A MIG is the way to go. I can do some clean Oxy/Acl welding, but it takes for ever and the amount of heat required can make life hard. When you use the MIG, becareful not to let the weld completly cool before starting the next burst. If it does, you could end up with slag in the weld causing a weak spot. That will be a sweet car when you are done. I like my 69 1750, but I'm having a hard time keeping it close to stock (the more power bug is running rampant.) The US spec cars are rare, only 640 made.
Good luck with your project, if you need some year specific pictures, let me know and I will try and help you out.
1959 101.02 Sprint AR1493*20198 (project) 1969 Datsun 2000 roadster
1988 BMW E30 M3