tiger, the trick with all the feed-out string reels is to stop before the string breaks off right at the reel. Once it does that, it takes perhaps 2 minutes to get it back into operation. Well, that's how long it takes me, and until I'd practised a bit it could easily take 15 minutes.
So far as the bump feed itself goes, I prefer it with the bump knob removed so you can hand feed it in about 15-20 seconds, and it never feeds by itself, plus the knob doesn't get in the way when you are snipping. However I've been advised by an expert that it is better yet to toss the feed reel entirely, and fit a simple string-holding device that just holds one piece of string. When the string becomes used up or broken, you just install another piece in a few seconds. I haven't tried that approach yet, but I can't recall seeing a professional use anything else.
