I also tried out stacking 12% for loader on the CGC, it takes ~2 sec off the reload. but the boost from 12% to gunner is night and day (need to do the math for the exact numbers, but there is noticeably less bloom, faster aim, and better accuracy after you fully aim in).
Yeah Arty shouldn't be able to use these bonus's but I guess there's a lot of things arty shouldn't be able to do. And you still play the CGC? Disappointing