I wouldn't recommend any kick to counter a SB. Straight blast is all about forward pressure directed at the opponent center line. What's more important SB must be done at the right moment. Immediately following a destruction.
Lifting your leg while being on the receiving end of an SB will take you off balance making it easier for the guy Straight Blasting you.
This of course is the first 2 methods coming out of the RAT fight model. The point here is not to trade blows. It's about putting an immediate end to a physical altercation.
But if your just sparring trading blow for blow then I suppose the guy is not throwing his SB after a destruction or interception. Then I suppose you could counter with a cut kick. But then again this isn't really a SB done properly.
I checked out the link to your gym. That place looks sick. And I can't believe how low the gym fee's are. I've never seen such low rates for a top of the line facility like that. How is the owner expected to stay afloat? His bills must be high. I want a studio just like that.
"Poor is the pupil who
does not surpass his
master" - Leonardo Da