According to a thread on TalkBass, the 5-string EHB models come with BH2s in the P4 size, which is 117x32mm. That corresponds with the E6W dimensions given above, just about: 119 vs 117mm length. so the magnet length would be correspondingly longer, maybe another 10mm to 76mm. That makes more sense, given that the pickups are slanted. Spacing is 18mm at the bridge, maybe 17mm at the bridge pickup position, meaning 68mm from B to G. Add a few mm above and below, and a few more mm to cater for the angle, and a 76mm magnet looks about right.
Could I safely remove 1mm of wood at each end, carefully? I don’t think it’s beyond me. I have needle files and I know how to use them. 😬
EMGs don’t come with a balance control: if you want one, you have to buy it separately. It’s included with some of their EQ circuits, such as the BQC. I wonder if the control cavity is big enough for that?