Filtering does not really help with the clarity of a wine. It is only for already clear wines, it is to polish the shine, not get rid of much. As you stated Chitosan is perfectly fine for folks with shellfish allergies. One of the members of the wine club I am a member of drinks the homemade wine many of us have made from kits with Chitosan as the clearing agent, without a problem. Short time frames and good wine, pick one, you can't have both, even if it is lower end kits. I have had some very good lower end kits, where folks took their time. I have had some really not so good high end kits, where folks rushed. This may be your only chance to give some folks a taste of good homemade wine and it really can be just as good as commercial, but only with the proper time allowed.