BL KK does suck on block, so you don't want the opponent to see it coming. There are some ways to do that...
50/50...
Everyone can see BL KK coming whenever you use 3B,A or 6A,A.
The basic simpleton way to avoid this is to use BL A, or RO AK.
After that, it works okay, it should become a 50/50 for the whole game.
If you used BL A and really want your BL KK, you can follow with LI AA, BL KK.
If the opponent is the kind who is successful thanks to lots of bullshit, and thus is knowledgeable about typical bullshit, you can instead opt for:
BL A, LI AA, BL A, LI AA, BL KK. (6A,A,A,AA,A,AA,KK. So much skill.)
Loops.
You can vary your strings to incorporate or remove BL KK. Some examples that I use frequently and some that I've found just now...
4B,PSL3,RO A, BL KK. (Most good players don't seem to recognize RO A... Only 6A,A and 3B,A.)
3B,RO A,PSL3,LO BK. (Obvious but...replaces one dangerous attack with another.)
a+bG,PSL3,NS,BL KK. (Natural shift, if they're scared of a+bG,A.)
If you think it's wiser, you can bait for a combo with:
a+bG,PSL3,LI K.
Loops are sweet.