RE:RE:Aces High RR$, every paper deal that I have seen sets the ratio at announcement. That means all the "time risk" subsequent to the announcement is borne by the seller.
That risk should be offset by a premium included in a paper deal, depending on the volatility of the stock of the buyer and the length of time before closing and freetrading. It also depends on the liquidity of the buyer when evaluating risk of a paper deal. IMG is a highly volatile stock, particularly when gold prices are low. Its volatility is about double Randgold for instance, so a paper deal from Rand is far less risky and would necessitate a lower premium.
Here is a great volatility calculator to use if you are ever evaluating risk between US stocks:
https://www.fintools.com/resources/online-calculators/volatilitycalc/