For me, 4B+K's back step works well after..
..1K tip range hit, vs short BB characters.
..2A tip range counter hit, vs short BB characters.
..BB tip range guarded or hit, vs short BBs.
..B>4 tip range guarded, vs short BBs.
..b6 tip range guard or hit, vs short BBs.
Against short BBs, if I spot them on time, I use SSH'K to counter between BBs after the 1st B whiffs.
Against farther BBs I use SSH'A+B to retreat & punish.
Against long BBs or 6B thrust moves that can hit SSH'A+B, If I gamble & spot it, I used 8_2B+K to dodge it, it works depending how slow the thrust is.
Another use for 4B+K that I have is to 1st built pressure with RSH'A+B, if it hits, I do another RSH'A+B. The 2nd RSH'A+B can be interrupted by BBs. If my opponent does interrupt my 2nd RSH'A+B, they might try it again, then instead of doing RSH'A+B hits to another RSH'A+B, I do RSH'A+B hits to RSH'4B+K into long back step SSH, then depending on my range from opponent I'll punish with SSH'K or SSH'A.
Sometimes the spacing from this set up is wide enough to try & counter hit with SSH'{B} & launching my opponent to be juggled with SBH'{K}.
A trick to set up my opponent to counter hit SSH'K is to spam SSH'A+B, this tends to force choice my opponent into jumping or doing ranger moves which are slow enough to get counter hit by SSH'K. This is similar to GI-ing often during -2 to -4, so that if my opponent tries a slower move to punish my possible GI whiff, I can gamble with K, 6K, 1K, or 66K to counter hit my opponent if does tries a slower move.
This is game play is similar to ABARE play. It works for me to soul crush my opponent while maintaining the leading role during rounds. This works tend to work well vs average adaptive opponents. A lesser adaptive opponent could end up out poking me sometimes by mashing senseless, unfortunate because of Sig's average speed. VS a more adaptive opponent I have to hold back a little to check on their reaction without blowing my cover, & spam less.