I've done this and the biggest recommendation I can make is don't even bother with trying to drill out the blind pin.
I just used a chop-saw to cut through the entire barrel and shroud just about 1/2" below the blind pin (ie, closer to the receiver than the muzzle). You're going to have TROS or whoever cut another several inches off anyway so why bother trying to make it neat, just hack through the whole danged thing and you won't even have to worry about unscrewing it, it just falls off if you cut far enough back.
You'll still need to grind/thin down a wrench to tighten the new barrel on but that only took a few minutes with a grinding disk.
Honestly the hardest part is just filling out all the paperwork, waiting on approval, getting the engraving done, shipping the barrel around (if you buy the CMMG SBR barrel you can avoid this but then you've got an extra half-chopped barrel you don't need), etc etc. It is a good opportunity to learn about Form 1's and NFA paperwork though.
Also be sure to use the dowel trick to keep all the pieces together if you do it yourself.
It's pretty simple really, the instructions on AR15.com make it look harder than it is (in my opinion).