I've done the hulda one and the Dr. Schulze flush. As much as I love pretty much everything Schulze, I have found the hulda one to work much better and be much more powerful. Funny you should mention high fat....I have done a couple hulda flushes where I ate extrememly high fat the day of (cheesecake anyone? lol) and they have been succecssful.
If it i power you want, things I do to make the flushes more effective: doing a flush after a master cleanse lemondae diet, I also get some tiger balm and rub it on my ribcage during the flush, and of course, talking to and "wooing" my liver during the process (ask hopinso!)