Hi Flyertalk community, its newbie aka lowly green member here.
I have tried to redeem a HKG<->KIX Business Class reward for myselfand a companion in Late Sep/Early October, with preferences to leave KIX in the evening.

The agent put me on CX507, 595, 569 on 5th October waitlist and told me likely I will get the seats. At the same time, he told me there are other flights in the morning freely available.

My waitlist expires 3rd April, but a portion of my miles is expiring 31st March, 2015. To avoid mileage expiring, is it true that I must have my booking confirmed by that day? (i.e., my redemption must be completed with confirmed tickets by that day)
If yes, with the experiences from the true CX frequent flyers perspectives - is my chance slim for those 3 flights?

Thanks in advance.

Yes you need to redeem by 31 March, and continue to waitlist

Here's KVS for the day's flights:

Carrier
Flight From
Depart To
Arrive AC/St
Dur'n Go
CX 503 KIX
10:00 HKG
13:00 773/0
04:00 Info
Seat Map
J9 C9 D9 I9 Y9 B9 H9 K9 M9 L9 V0 S0 N0 Q0 O0
CX 567 KIX
09:20 HKG
12:20 333/0
04:00 Info
Seat Map
J9 C9 D9 I9 Y9 B9 H9 K9 M9 L9 V0 S0 N0 Q0 O0
CX 507 KIX
18:00 HKG
20:55 772/0
03:55 Info
Seat Map
J9 C9 D9 I9 Y9 B9 H9 K9 M9 L5 V0 S0 N0 Q0 O0
CX 595 KIX
18:40 HKG
21:35 77W/0
03:55 Info
Seat Map
F6 A6 J9 C9 D9 I9 W9 R9 E9 Y9 B9 H9 K9 M9 L9 V0 S0 N0 Q0 O0
CX 569 KIX
19:00 HKG
21:55 333/0
03:55 Info
Seat Map
J9 C9 D9 I9 Y9 B9 H9 K9 M9 L9 V0 S0 N0 Q0 O0
CX 565 KIX
11:00 HKG
15:45 333/1
05:45 Info
Seat Map
J9 C9 D9 I6 Y9 B9 H9 K9 M9 L9 V0 S0 N0 Q0 O0

Thanks a lot percy.
With these inventory figures I believed it is green light for waitlist.
But when should I stop wait and change flights by paying $?

You don't have a choice - you have to use the miles by 31 March unless the amount is insignificant and you can afford to let them go.

I will try to call them right away for taking the seats first then.
Might be I should confirm the waiting and then wait for the other flights by paying fees

or darn it , redeem First class on the way back..

Redeeming the plan B flight that you can live with whilst waitlisting for plan A is usually the best way to waitlist for a not-available flight.

Tickets issued - thanks.
Well I dont know why but the staff at call center persuade me not once but twice to redeem for tickets on 6th...