At three weeks, it's unlikely that the yeast is doing anything meaningful taste-wise, and clearing is really a time/temperature thing, not a yeast thing.
So I'd bottle it now. Carbonation should take ~2 weeks at ~70 degrees.
If you want the beer to clear well, you can do two things:
1) Add a bit of gelatin to your bottling bucket.
2) Once the beer is carbonated, put them *all* in the fridge.
Gelatin will help clarity, and cold storage will help clarity. So if you have the capacity, leaving beer in the fridge for a few weeks before you drink it will help things drop out of suspension.