The problem with 49th ave is that it is essentially a single lane road in each direction. It can get quite congested as people try and turn both left and right at an intersection. Case in point places like Victoria, Fraser and Main. I can see them increasing the frequency of the #49 bus. But I just don't see 49th being able to handle a B-Line.
A B-line on 41st ave is better if they were to remove the parking along the curb (during peak hours for now and possible longer in the future) from about Victoria to about East Boulevard. And turn it into a bus only and possibly HOV lane. That would let the B-line bypass a majority of the congestion. With Kerrisdale being the only real problem area
I also think the best route to BCIT with a B-Line from 41st would be down Joyce Left on Boundary, Right onto Kincaid past the Hospital onto Sanderson and down to Willingdon by BCIT.
Now Joyce I think would need no parking along the curb during peak and possibly a Bus only lane. As it can get very slow going through there. For some reasone people think doing 40 is ok in that area
The other problem I see is what happens when the B-Line comes from BCIT up Kincaid and gets to Boundary. It now has to make a left turn at Boundary with no Light. So why not install a Pedestrian activated light. But set it up so the buses can trigger the lights themselves by proximity. Although not sure if that is possible