If you want damage after your B3, 2 pop up, do this:
B3, 2, slight dash 1 xx EN Gunshot, slight dash 1 xx Roll Toss. Does 33% I believe(36% with a jump in punch), which isn't too shabby considering it's your low string and not the launcher. You can replace the dash 1 xx Roll Toss with a dash uppercut(32%, 35% with a jump in punch) to gain zoning advantage. Depends on the match up. If you don't want to waste a meter, just do that same combo minus the EN Gunshot(replace with regular Gunshot) and end it with a dash 4. Execution is really tight, though. Could end it with a dash D1 if you're not feeling the timing but does significantly less at 23%. Does about 28% with the dash 4 I think, 31% with a jump in punch.
I find it's better to use 3 after a FJP so they don't gain a wake up opportunity or roll back away from you. Does 8% I think, but is worth it because it limits their options. Props to Police Brutality for the 3 after FJP, though. Learned that from him. Also, note that the hitbox of the boot will look like it won't hit, but it will with the right timing. If they're in the corner you can just repeat 1, 2 xx Gunshot twice and end with a 4 for like 25% if you're fishing for damage, but going for a 3 after the first 1, 2 Gunshot isn't bad either at 17% and the reset situation.
EDIT: I realize that is kind of confusing/muddled together so let me put it down individually.
B3, 2 -> slight dash 1 xx EN Gunshot -> slight dash 1 xx Roll Toss - 33%, 36% with FJP
B3, 2, slight dash 1 xx EN Gunshot, slight dash uppercut - 32%, 35% with FJP
B3, 2, slight dash 1 xx Gunshot, slight dash 4 - 28%, 31% with FJP
B3, 2, slight dash 1 xx Gunshot, slight dash D1 - 23%, 26% with FJP
FJP, slight dash 3 - 8%
FJP, 1, 2 xx Gunshot, 1, 2 xx Gunshot, 4 - 25% Corner Only
FJP, 2, 2 xx Gunshot, 3 - 17% Corner Only
Also don't neglect Baton Sweep as an ender as it gives you an untechable knockdown, putting them at your feet to continue pressure.
B3, 2 -> slight dash 1 xx Baton Sweep - 20%(25% with EN), 24%(28% with EN) with a FJP