I use fire groups, and have no issues with KWS scan time hunting in anarchy, I now can almost forget I am scanning and it just happens on its own. This is how I am using KWS with my cobra:
Group 1 - Button1: KWS, Button 2: Interdicter
Group 2 - Button1: KWS+beams
Group 3 - Button1: KWS+beams+multicannon, Button2: Shield charger 1
Group 4 - Button1: KWS+beams+multicannon, Button2: Shield charger 2
I use the chaff key bind no need to put it in a fire group.
I can't use the shield charger key bind as I have 2 fitted and this fires both together.
small ships (easy cobra and smaller):
start with group 1, part way through the scan switch to group 2
if you keep the fire button pressed, the KWS continues and the beams start killing.
only switch to group 3 if their FSD starts charging.
big ships(hard cobra and bigger):
start with group 1 or 2, then group 3 once the shields are down, switch to group 4 if your first shield charger is empty.
kws is 10 seconds, and that's a long continuous blast from guns, using the kws only (group 1)first shortens the scan under fire time. with practice most ships will popping one second after the scan completes. some may pop too soon but that's practice.
once one scan completes, you no longer need to perma-fire button1, use your normal attack patterns from then on
triggering partial scans after the first completion seems to have no detriment, so binding it to fire buttons is fine.
if a big ship is going down fast i'll just kill it, but if it looks like I'll be using ammo and shield charges and i'm not sure a bounty was detected, i will check the contact details for the ship just to check its work finishing the fight.
most small ships go down without using ammo so, they get killed bounty or not.
I am in a federation anarchy system, and when only targeting Wanted ships the bounty from emipre is easliy 3x more than what is paid by the local feds.