should be a problem... installing a wall mounted or ceiling mounted?

Will you put Plastec Ceiling? If yes, than you need to make into consideration.

Gap between Curtain and windows will need at least 3 inch (7 cm)
Gap between Aircorn point and ceiling or Plaster ceiling is 15inch (38cm), this is good for 3HP too. (need consider if you put in downlight)

As I just facing this problem after inplace plastec ceiling and endup need to hack the aircorn piping again.

For my case, i did plaster ceiling...follow by a.cond and finally curtain.

You are enough.
60 - 7 = 53. So you have 53 cm to put your aircorn assuming you will not put plaster ceiling lol

You have 17 cm  (53-38) to play around the gap with the track and air corn lah.

You need to those the aircorn folk who install the pipi where and how high your track be, they will know how to arrange it.

How my aircorn folk measure is start from the "bottom of the aircorn water pipe" till 15 inch, those will belong to aircorn. 

I have done by aircorn piping around April, where the aircorn folk have done a good measurement which allocated 22 inch from pipe to the root, included 7 incn after plaster ceiling. But end up it need to drill again, as the plaster ceiling folk make it 9 inch, which cause the pipe and plastec ceiling on leave 13 inch. With this 2 inch I have to pay extra to drill again as I didn't want to open a Box at the plaster ceiling.

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This is another area which short of almost 4 inch after plaster ceiling in place  , and you could see how the whole measure should be, and ease you to understand

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Get the aircon seller do it, as not only included hacking your wall but also need to fill in gas and so on for your new aicron. 2) Any problem on the aircon you still could ask the aircon seller to support 3) Your contractor not specilist on aircorn