Tongue block 2 draw full bend tips?

Thank you so much for a great course, I am very much enjoying it.  I know variations of this question have been asked a bunch before, but mine is a little specific.

I've been working over the past month on my bends with tongue block (A harmonica, Lee Oskar) and I can get all of them except for the 2 full bend.  I can get a strong 2 full bend with a pucker, but not TB.  

Here's the rub, I can feel how deep the back of my tongue gets when I pucker a -2", and I feel like i can't physically get my tongue base that deep with a tongue block b/c the front of the tongue is on the comb.  

Other than growing a longer tongue, are there any tips on how I can try to get that mouth resonance deeper if my tongue can't go down further?