This is just my experience with gelatine used as finings - I have not had a problem with it. I've done a heap of extract lagers now and more recently FWK's and the lagers have been really clear. I've not had any issues with the gelatine whatsoever. I've stopped using it for my hazier pales and should I try darker beers later on I won't be using it for those either.
My method is quite simple when using the product - From memory @BlackSands BS, shared his process a while back. He can correct this if I've ballsed it up - but this works for me.
approx 250ml of cooled preboiled water in a sanitised small container.
1x Teaspoon gelatine sprinkled into the container of water.
Let the gelatine bloom in the water for about 15 minutes,
When the 15 minutes is up place the container in the microwave and heat on high for approximately 45 seconds or until gelatine crystals are completely dissolved.
Using a sterilised teaspoon stir the contents to make sure its completely dissolved.
Gently Add to fermenter when cool making sure it's distributed evenly into the wort.
That works for me but that's not to say it's the correct method or it will work for everyone.