I am no expert, but I do a little gun smithing on my own guns, I don't see advantage or disadvantage of external or internal extractor, it's all individual AND more importantly, depends on adjusting.
I have Colt Gold Cup that is internal extractor, it's definitely not inferior to my S&W659. In fact, after adjustment and polishing the ejector port, the shell flew out much farther than the 659 and not tumbling when coming out.
If you were to doing your own modification on the extractor, I would buy a new extractor to do all the adjusting and keep the original one untouched. So if you screw up the new one, you can always go back to the old one and you're good to go.
I've seen video in adjusting the tension on both kinds, you can easily find those.