Traffic at Changi on any day is the same, my friend. BUSY. The peak times are from 7-10am and 5 to 11pm. If you're thinking of spotting, I've got a couple of recommendations. There's a car park at the northern end of runway 20R. At this time of the year, the planes will be coming in from the NW to land at the 2 parallel runways, namely 20L and 20R. This is a very good spotting, and you'll see what I mean when you're there.
You'll typically see lots of wide-bodied aircraft at SIN especially during peak periods. My favourite time is from 5-7pm when lots of flights from Europe come in. There'll be an aircraft coming in every 10 minutes,on average.
Another good spotting location would be along Changi Coastal Road. This road runs parallel to runway 02R (or 20R, depending in which direction the planes are coming in). Excelent views of a/c parked at Terminal 2 and on the runway.
I hope this bit of information helps, my friend. If you want to know the schedule of flights coming into SIN, go to: www.changi.airport.com.sg There's a link that will take you to the flight information menu where I'm sure you'll have a ball. : )
Looking forward to seeing some great pictures here very soon!