No one can give you absolute certainty on where this stock is...

No one can give you absolute certainty on where this stock is going to top out, or that it won't go into decline. That's the nature of investing; there can be so many unforeseen circumstances that alter the share price sharply up or down overnight.
People don't like uncertainty, and right now, investors will be sitting back (some selling) while the merger process plays out.
Those of us that have more of a long term strategy, are not too concerned with the daily price changes and have a strong belief in this company and with that, think it is highly probable that the share price has considerable growth in it yet.
Assuming that the merger goes through and that the new DFS is favourable, larger investors and the likes of super funds will pay a lot more attention to GXY.