I certainly haven't done it to the repetition rate suggested, but have been practising like that on and off for 6 months. In practice I expect to hit them all from 6 meters (I don't always and often miss one from shorter as well.) ON the course I do now feel fairly confident up to about 5 meters - this time last year it was 3 meters! At the recent competition over three rounds I think I only missed three putts from within 5 meters, which for me was great, and these were all spitouts, I didn't can any from further out than about 8 though.
I do release before the elbow straightens and there is definite late acceleration, I have over the last couple of weeks really concentrated on keeping it relaxed to help with this and it seems to be working. I am getting definite finger spring. I tend to straddle putt out to about 8 meters, for the first 4 or 5 I don't really involve any part of my body below the waist, maybe a bit of knee bend. Further out I start using the knees to generate a bit more distance, I tend to start missing low though as out on the course I don't fully commit to these shots. From further out I go to a more traditional/slightly offset stance as I have a habit of forcing it too much with teh straddle. I have been practising this a lot recently and its really starting to work well. It fails when I fail to fully commit to it and it will either hyzer (when I try to force it) or go high (when I don't shift my weight properly and pull out of the shot slightly at the last second). I had a good round last night where I canned three shots between 10 and 15 meters out all of which were slightly pressurised as they were to save par so the practise does feel like its starting to pay off.
The biggest issue I have is my own confidence. at my local course the baskets are on the full size of the PDGA specifications, they are all at the same height and are very easy to hit. At the other courses I play round the country the baskets tend to be smaller than regulation (or at least right on the edge) and will be at completely varying heights from the ground. I know this shouldn't affect me but it does. Its why I've built a basket with varying sizes for the chains and variable height, to try and get myself ready for changes in baskets at other courses. One day it will all pay off!.....possibly