Bigger numbers indicate greater liquidity. Size changes throughout the day so savvy investors track it closely when attempting to buy or sell shares. The size is available online if you have access to real time quotes, or through your broker. If you decide to buy or sell a large block of a thinly traded fund you may want to break your order up into several smaller ones and feed them in gradually to avoid putting excessive pressure on price, thereby minimizing market impact costs. The careful placement of limit orders can be a great way to minimize trading costs.
Limit orders are instructions to buy or sell at a specific price or better.
By using limit orders and being patient you'll often receive a better price than buying or selling at the market. Closed-end share prices fluctuate more than their NAVs. A fund's price might bob up and down a quarter or even a half point during a day. Some people will go in a bit below the bid or above the asked. It depends on how much of a hurry you are to buy or sell.