I just installed shoe molding in a closet and IMO it's not as easy as one might think - you need a long nail to hit the stud, your angle must be very shallow to avoid hitting or interfering with the HW floor, and either the drill or hammer can easily damage the HW floor.

I can't use an 18ga nail gun because the longest nail is 2" which won't hit the stud. I nailed with 2&1/4" 8d finish nails - overkill but I think you need that size nail so it won't bend since I start using the nail set ASAP. I am using the Timbron shoe product. Here is my procedure-

1. Locate studs since studs easier to hit than plate in my case.
2. Predrill shoe in these locations with a very shallow angle.
2. Protect HW floor where nailing with tarp and hardboard.
3. Nail using nail set.

Even with the 2&1/4" nails I barely hit stud sometimes - about 1/2" shoe + 1/2" base + 1/2" drywall should leave plenty of nail but I suppose sloppy framing can add an extra 1/2" or so of space. I suppose I could use my 15ga finish nailer with 2&1/2" nails but I don't know if there would be any real advantage.

Is this a good method?

It's not necessary to hit the studs when nailing shoe molding. We use 18 guage finish nailers - 2" nails, and caulk any cracks between shoe and base, that's about it. We sometimes install 700-800 ft per day.

So then what do you hit, the plate?

I have 3/4" ply over slab so that's the only reason I said I have to hit the stud - obviously a unique situation.

I still think that in my house even w/o ply over slab the 2" nail would barely hit the plate. Also, high end trim installers often shim behind the base so it's perfectly straight instead of following a wavy wall.

Well, you have base board, right? Nail the shoe to the base, it'll stay just fine, push tight to the floor and wall and nail , nothing more is necessary.

Ok, you must be installing the shoe vertically (long dimen against base). I see it done both ways but vertically makes things easier.

Yes, if you want it to come further out on the floor, use Quarter round- it's 3/4x3/4".

we always nail the baseboards to the studs, 2inch nails.
for the shoe we use 18g 1&1/4 and nail it to the base, its not necessary to nail the shoe to the studs