I have used the Biofine and would not recommend it for unfiltered beers. After explaining our procedures to our supplier, he recommended this as an isinglass replacement for Murphy & Sons Caskleer paste, which they had stopped carrying. I noticed that while it flocs out the yeast very quickly it never really packs tightly.
In addition to fining casks, we treat some unfiltered beers with the isinglass. It is dosed inline throughout the run. Two days later, we dump off the dirty beer in the bottom (dish bottom, no standpipe), approx. 1-2 gal in a 15 bbl batch. It runs clear after that (looks filtered) until the very end. When we open the tank after it is empty, there is just thick yeast, tightly packed on the bottom.
After using this same procedure with the biofine and giving the beer a week in the tank (with a standpipe), we began to keg off the whole batch for distribution. This tank had no sight glass, but we know our typical yield. When it ran dirty early we were flummoxed by the low yield. Lo and behold, we open up the tank to find 2 bbls of muddy beer. We had done some rudimentary trials and fined some casks and felt we were in the right range. Upon discussing this with my supplier, he stated that it was really intended more for beer that would be filtered.
We are now using Murphy & Sons Magicol 250 AS. It is a dried isinglass preparation that works the same as the paste. You'll need a high shear mixer, like a wand mixer from any home store, and it needs to be prepared several days in advance, but works well. We are now working through the rest of the biofine for cask fining. It works ok for that. Not great, and you'll have more loss if you like to serve clear cask ales.
Hope this helps and it's not too late!
Blackstone Brewing Co.