Currently, I can only buy NO/YES if I have bid YES/NO, but I would have to estimate how much my shares are worth.

This market resolves YES if I have at least the same option that I have in free response markets, where under trades by you, there is the option to sell your previous bets at current market prices.

I think manifold is working on this new type of market for the World Cup, so I assume that it should be top priority.