It will be roughly 8,500 Triway shares for every 10,000 SIAF shares. Becuase SIAF is spinning off half of their 36% stake, or 18%.
On or after the ex-dividend date, the SIAF stock will go down by roughly 20% (because SIAF now owns less of Triway, and the market will account for that).
As for the value of the shares, Triway is worth $350M and has 100M shares outstanding. So for your own administration you can book $3.50 for every Triway share you own. On paper, that is. You may be taxed as well, which would make it kinda official.
What the shares will be worth once listed in Hong Kong is a different matter. Much higher, if the IPO is a success.
That's all there is to it. It doesn't matter when they make the announcement or if there are any delays. There's not much you can do with the shares until you can sell them on the HK market.