Time acts as a great fining agent for kits that don't have fine, suspended particles. I personally have not used fining agents on one of my kits for some time as I let them bulk age for a bit before bottling. Topping up with a commercial wine will not provide an adverse effect in your kit (provided you top red with red and white with white in general). If the wine ends up being clear enough for your taste, then why not just leave it? I believe, 'why strip when you don't need to,' although that is just my humble opinion.
Two important notes: 1) Add 1/4 tsp. of K-Meta to your bulk-aging kit every two months to keep sulfite levels up. 2) If you are using oak cubes to oak your wine, use a small amount and then test the wine on a regular basis to see how it's coming along.
- Jim