Hi,
I was hoping someone might have gotten back to you because I’m heading to SIN at the beginning of July and plan to do some spotting too. Alas, I found these two sites which seem to have a lot of information on spotting at many airports worldwide;
http://www.spotterguide.net and
http://www.spotterswiki.comWiki might be a bit out of date as it says it was last updated in 2007.
I hope to find a location that has a bit of elevation but it doesn’t look like there is anything??
Let me know if you find out any more.
Have fun.