I think the first step with clearing a hazy beer is figuring out the root cause. It could be biological (low floc yeast, contaminants, etc), protein-polyphenols, beta glucans (oats, wheat, etc), or water chemistry (calcium oxalate).
This could explain why certain products work on some beers but not others. I recall Ken was having an issue with some of the products on the market with some of his beers.
I have settled on Brewtan B in the strike liquor, mash pH control, 50+ ppm Ca in the mash, lautering clear wort to the boil kettle, whirlflock in the boil, whirlpooling the bitter wort before transferring to the fermenter, pitching a lot of healthy flocculant yeast strains, cold temp and time post fermentation. This combination works well for me.
I also used to use gelatin routinely but rarely use it anymore. I tried it again recently on an Altbier I used K-97 on and it helped a little but that beer became brilliantly clear after is sat in the keg a while.