I don't know if anyone else would but I've had bts for a couple years and this year is my first breeding year. Personally I would never probe them, I'd be too afraid to hurt them. They are not as hard to sex as most people think. I've sexed 5 out of 6 right and was not sure about the 6th so I put it with a female. When nothing happened I put it with a male and the male bred her, telling me exactly what sex she was.
I have a sexing page for blueys on my site and I'm sure if you do a google search you will find more. I'd definately go by the size of head and hemi buldges before probing any day. I don't know if you can actually probe them, it might do more damage than anything.
If you want to see the page on my site go to sexing reptiles and then the sexing blue tongues page. Good luck.