I`m also fan of J50BC, but I`m using it in my Charvel Model 6 without plastic cover (can rise closer to strings) and without midboost.
Tried setups with EMG 81X (hate it), 85 and AHB-1, but liked J50BC (reinstalled several times), don`t tried JE-1200 midboost (previous owner removed it), used some time with EMG SPC instead, but it acts like debooster with distortion (with uncovered J50BC)...
Tried setups with EMG 81X (hate it), 85 and AHB-1, but liked J50BC (reinstalled several times), don`t tried JE-1200 midboost (previous owner removed it), used some time with EMG SPC instead, but it acts like debooster with distortion (with uncovered J50BC)...