I agree more with B35's idea here. However, I see what you're trying to do with the two B8 branches, and my counter proposal is this... (this was originally his idea in part, so I'll give him credit for that....)
https://maps.google.com/maps/ms?msid=213458373195564989412.0004d0932f6237afe56b0&msa=0&ll=40.642615,-73.918247&spn=0.037709,0.077162
Here, I took the B8 off of Avenue B completely, and rerouted it along Kings Highway to somewhat replace the B7, which would be rerouted to replace the E. 80th Street branch of the B17, providing extra service to the area.