one thing I'd like to point out is that you wont be able to fly with your guitar as carry on. This is not a Singapore Airlines issue (because you sure can fly TO Hong Kong with it as carry on) but the Airport Authority in HK does not allow guitars as carry on.
(I've only done this with a soft gig bag, not a hardcase).
You can have it tagged at check-in and carry it to the gate, but upon boarding they will take it and put it in the hold with all the baby strollers. You have to wait upon disembarkation to get your guitar back at the door of the plane with all the mums and dads waiting for their baby strollers.
I'd opt for a very rugged hardcase or flight case if you can find one (check ahead if you can source an SKB case in HK). detune the strings, make sure the neck is protected, get a fret protector (plastic sheet between the strings and frets) and tons of Silica Gel packs to stuff in the case (absorb the condensation). Also leave the guitar to settle to the ambient temperature in Singapore for a while before you tension up the strings again.
Are you sure you can get a good deal in HK? I haven't seen prices that favorable there.
Good luck!