For some destination like LHR, the restriction is so great, you have to book 11 months in advance !

While it is not possible to book suites SQ322 in saver, why not try their 77W F or 388 R if you haven’t try it before? Generally, saver are mostly available on SQ318 F or SQ 308 R. Those seats are pretty much as good as it gets!

Ya, saver is very popular, especially to LHR. Usually availability is open 330 days before the flight and a limit of 2 tickets will be allocated.

3 tickets automatically goes into waitlist

It is totally depends on the demand and load factor of that particular flight. Sometimes even with empty seats, they won’t confirm it , due to the high yield it generates from last minute booking, especially the flight to London. It is best to have a confirmed booking for this destination. If you are travelling in a group up to 4 pax, why not make booking on 2 different flight on the same day? Eg 2 travel suites on SQ308 and the other travel 1st class SQ318. That way, you can have confirmed booking!

Sort of... but doesn’t happen every single day, probably few days in a month.