I guess it depends on how you trade, once you get those 'free' shares...
IMO, the only way I would do it, would be if I would be willing to sell those 'free' shares after they ran up another, say 20-30% from where I last sold the other shares. Of course this 20-30% number totally depends on the scenario... whether it is a breakout, a bounce, or whatnot.
So what usually happens in the types of plays I am using is that if I sell the second 'batch' of shares, they will happen probably within a day of my previous sell. If the shares go back to the highest previous sell price, I will also sell.
Ex: If DRYS runs to 10, and I sell the majority of my shares and are holding say 100 'free' shares, then if they run up to 12, then I will sell them. If they fall back under 10, then I will sell. If nothing happens within 1 day, then I will sell.