I'm not sure either if I'm looking at the right info but according to Quebec Whitewater and the CEHQ gauge I'm looking at (Fleuve Saint-Laurent #001003), the Lachine Rapids may be good right now for the Gaetan, Pyramide, and Guy waves but not so good for Big Joe. The little wave at Habitat 67 is apparently in above 7800 m3/s. According to the gauge, it looks like the flow was just under 8500 m3/s today.
I've got some plans in Montreal tomorrow so I'd probably only be able to paddle on Sunday... We were planning on leaving early-ish tomorrow and coming back sometime in the afternoon/evening on Sunday.
Were you thinking you'd spend just Saturday or both days in Montreal?