1- Like he said: Personal preference.
I like Heinies.
2- Almost like #1. If I were building one right now, I’d probably try a Kart Easy-Fit barrel/bushing. I like Bar-Sto also, but they can be hard to get at times.
And there’s nothing really wrong with a plain old Colt barrel either.
3- For me- neither ramp cut. I’d get a standard frame for a non-ramped barrel. I don’t care for ramped barrels, at least on a .45. I dont see their need on the .45, and the resulting feed angle is steeper than the standard two-piece (frame/barrel) feedramp.
4- I have two guns with external extractors and have had no trouble with either (Kimber and S&W). But given a choice, like I would if building it, I’d get the internal extractor. For the most part, once the internal extractor is right…it’s right. It isn’t the black magic some would have you believe.
The internal is available from most suppliers (if you would ever need another), and it’s easier to remove and replace for cleaning the extractor and it’s cut in the slide than any external I’ve messed with.
Heinie makes a sight that fits in a Novak rear sight cut. IMHO the best way to go on any 1911 is with the Novak cut. Just about everyone and their brother makes a sight that fits that cut (Novak, Heinie, Dawson, Warren Tactical, 10-8, Yost, Champion, MMC and SDM come to mind). I can’t think of one other sight manufacturer who makes a sight to fit the Heinie cut. It gives you some flexibility if you don’t like the sight picture or if something else comes along and catches your fancy.
+1 for the Kart Easy Fit. I just put one in my Springfield TRP and couldn’t be happier. I figured since this was my first time fitting a barrel I’d really screw it up, but now it shoots one hole groups at 25 yards if I really try. I’m starting to build a 9mm 1911 and there is no doubt I will use another Kart barrel.