How deep to bend when doing a 3 4 trill

Hello Dave,

Here I am with another musical dilema.

I am curently trying to learn the 'mean old world' piece by little walter.

The recording where he does a lot of 3 4 trills.

On the solo he goes into a 'bent trill' and then releases.

Thats pretty common in other pieces as well in a couple of songs i have studdied here.

So my question: how deep can I afford to bend that trill before it nolonger sounds musical? 

can it be 3''' 4' or i should aim for 3" 4' or even 3' 4' ?