RE: Draw weight
When I was in my teens I used a bow that went up to 60 lbs. Every bow I've purchased since then has been 60 to 70. A bow that has a wider range of adjustment ismight bea good starting point. 55-70 or 50-65. What you have remember that some bows that are 60-70 may adjust lower than 60 lbs and some bows in that range also have a higher max. My bow is 60-70 but maxes out at 75.
The more you shoot the easier it will be to draw and hold a particular draw weight. Working out also helps. However, you can also get caught in the trap where you have no problem drawing a weight standing there in the middle of summer. But when hunting season starts and it's cold and you are sitting you can't draw. I had this happen when I was in my late teens on a nice buck.
Ultimately, the draw weight you use for hunting should be easy for you to draw sitting down and at all angles with hunting clothes on.
As for dynamic spine. You can shorter an arrow to increase spine, add weight to the back endto increase dynamic spine. Remove weight from the front to increase dynamic spine. Add weight to the front to reduce dynamic spine. If you are comfortable up to 70 lbs but your arrows are slightly weak you can decrease the draw weight a little to spine correctly. There are good programs to get you in the ball park now. But shooting the arrow and seeing how it tunes is ultimately the best way.
Most hunters I know prefer an arrow having a stiff spine for hunting.