speyman said:
Don't worrying about tongueing or not. This is not the problem.
Why not use the side C key when going from B to C. Hold the B key down and just press on the side C key. No flip/flop allowed on the L/H index and middle fingers when playing from B to C or from C to B.
Tonguing may not be the problem but it masks a problem that needs to be fixed. You'll need to be able to play b to c without tonguing it at some point.
The side keys are NOT always the correct keys. Our friend here has learned the fingerings in the normal order that is generally taught. There are reasons for this, like the fact that beginning saxophonists need to get comfortable with the stack keys before they move on to the side keys. All that extra movement will contribute to sloppy finger technique later that'll need to be unlearned. They shouldn't be moving their fingers from the regular position until they're comfortable with them.
Plus side F#, C and Bb on student horns often have less than optimal placement and intonation.
These fingerings are not a "habit" that needs to be broken, they're one of a number of possible alternate fingerings that are part and parcel of learning the saxophone. Any student eventually needs to learn all of them and when to use and not use them.
The "flip-flop" fingerings will only cause a problem if (like any other fingering) they're not practiced. I'm currently working on a whole new set of bass clarinet altissimo fingerings. They're very sloppy right now because I'm not comfortable with them yet. But they have both better tone and pitch.
The only way for them to become useful is to practice them and accept that they won't always be the right fingering for that note depending on the speed of the passage and the surrounding notes.
Sorry Speyman, I think your advise is possible quite damaging. The "flip-flop" fingerings are the accepted beginner fingerings for good reason.