I'm curious as to where you got that procedure. It might work, but I wouldn't describe it as French polishing. A 1 lb cut is fine. You can build up quicker with a stronger cut, but it's more difficult.
The idea that you can apply one coat every 30 minutes suggests to me that the method involves using a quite wet rubber, doing one pass over the whole surface, not worrying about getting it flat, and then repeating. This is not French polishing - it's just applying shellac. Although it can work, getting a smooth even finish by sanding back a rough surface is difficult. There's always a risk of rubbing through to the wood, and the finish is likely to be patchy. This will be particularly noticeable if you're using anything other than a blonde shellac.
The method I was taught (and what I believe to be the traditional method), is to apply the shellac with a relatively dry pad, so that there are no "undulations" that need sanding out. I talk about polishing "sessions" rather than coats. Two sessions are the most you're likely to do in one day - with only one session per day after the first few days. Each session will last about 45 minutes initially, and more like 25 minutes in the later stages (less time for each session when you have less experience, a bit more if you're using oil). Minimal sanding (if any) between sessions, and shouldn't need more than a light sanding before the final session (glazing) to get it perfectly flat. Glazing session I use a really weak mix, and some oil.
I've never understood the need to "push" down on the guitar during polishing. Risky on the top, and no benefit I'm aware of.
So the short answer (IMO) is no, but guitar makers use a wide variety of methods to apply shellac to a guitar, and I expect most of them can be made to work.
James Lister, luthier, Sheffield UK