Hydro assist question

For those who have drilled and tapped their own boxes for hydro assist, how many threads do you have engaged on the lower hole? I drilled and then tapped with a standard 1/4" npt tap. Once it bottomed out, I cut the tap so it became a bottoming tap. This still leaves me with only 2.5 threads of engagement. Should I redo it for more thread engagement? I've already rebuilt the box and would hate to tear it back apart to tap it more but I will if that isn't enough threads. The fitting is quite tight and took a good bit of torque.

If anyone has any answers, I would greatly appreciate it.

I did what you did, but ground my tap down a few times to get it in a few more threads. Ideally you should have your fitting tight just to the edge of the passage so it's not blocking the flow.but yea there's not much there.