717/720 engine, which cylinder to set timing to?

[jeffbeckib]

Finally getting around to swapping the engine on my 98 sportster 1800, and I have the timing tool for the rotary valve.
Does it matter which cylinder I set the timing to? If I'm facing the rotary valve, should it be set to the one on the left or the right? or it doesn't mater?

 

[Dr Honda]

The one on the right. (The MAG cyl)