Max Stretch vs. Coaxing the Tunica Gently

I can get fatigue at 7-9 pounds of tension

But my dick can continue stretching to a greater length than that all the way to 15ish pounds of tension

Do I want the greatest stretch possible or does that risk strength adaptation or too much collagen vs. elastin?

[FYI I’m generally able to avoid injury even at 15 pounds]