I happen to have an extensive experience with Sparkolloid, as it is one of my favorite fining agents. It attracts negatively charged particles that are remaining in wine during the final stages of the process and leaves the wine crystal clear in the matter of days. Having said that, I personally don't use fining agents that often, especially if my wine is made from fruit, as opposed to juice. In particular, I wouldn't recommend fining with Sparkolloid wines in which you wish to preserve the color, as Sparkolloid is pretty harsh and would strip it away. If I were you, I would wait as much time as you are prepared to spend making your wine, and if the wine is still not clear, then use fining agents.